DIY HDD platter swap? - Page 1
Forum section: electronics / general

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 02:24:44 am
content: I've been bad. No backups.My home server was running in a 3 disk raid and 2 disks failed within 24 hours of each other. Server is FreeBSD and the disks were in a ZFS RAIDZ pool. All 3 disks are 2TB Seagate Barracuda 7200.14 / model ST2000DM001/ PN: 1CH164-301 / FW: CC4HMy biggest mistake was not having any backups. My next biggest mistake was buying 3 disks two years ago at the same time which likely came from the same batch, and thus they might all be prone to a similar failure. There is approx. 18500 hours on each drive.I had 1 drive fail first: the motor spins, then click click click, then the motor spin down. The BIOS does not see the drive. If it does see the drive, it sees it as only a 4 GB sized drive. The 2 remaining working drives were always seen as 2000 GB each. With only 2 drives working, the ZFS RAIDZ pool was still working in a degraded state and I could still read things ok.So I picked up 2 new TOSHIBA 2GB DT01ACA200 drives to replace the broken one, and have a spare. These disks have slightly more logical sectors than the Seagates, so not a problem for a RAIDZ swap.Before simply just replacing the bad drive and let it re-silver, I wanted to make a backup of the important stuff. So I started backing up the important stuff onto one of the new drives, and before I could complete that task, the 2nd Seagate drive failed in the same way !! click , click, click, then drive spins down, BIOS won't see it. Now I have 2 failed drives and the RAID won't come up. I didn't get all the data off.Googling around shows me this is a common failure mode for the 2TB and 3TB 7200.14 Seagate Barracuda's. Wish I had known that earlier.There's also a 1.8V LVTTL serial port on the drive and some serial port commands for resetting things on the 7200.11 but warnings that doing the same commands to the 7200.14 will likely kill it. There's enough misinformation out there to warrant not trying anything like that just yet. Some of the commands are to clear the SMART data and especially reset the reallocated sector counts (like it ran out, and cannot start now, but I'm not sure)I'm thinking of doing the following:1) a sector by sector copy of the one remaining good Seagate drive onto a Toshiba drive.2) then trying to DIY a small cleanroom hood (just like like a chemistry hood, but with a positive pressure, HEPA filtered airflow outwards)3) open the good drive and a bad drive and do a platter swap, close the drive, then try to copy a second Seagate drive onto a second Toshiba.If that works, I can restart the server with the 2 Toshiba's and get a degraded RAID again.So, does anyone think I have a chance in hell of being successful (with a DIY clean room like this)?I would only need the swapped platter to last long enough to dump the sectors, which might take 2 to 3 hours , 4 hours tops. If I get a degraded RAID back, I just want to get my data off it, then reformat everything and start new.Does anyone know and willing to share the 7200.14 serial port commands that might breathe some life into the drive?Thanks!

author: SL4P
author_rank: Super Contributor
timestamp: August 01, 2015, 03:00:36 am
content: Quote from: codeboy2k on August 01, 2015, 02:24:44 am1)Yep - noting that the sector addresses will probably have little relevance to the RAID map2)Hmmm. But (at best) you want the HEPA on theinput'side' - otherwise you're sucking warm dirty air in, and on to the disks - then cleaning it to blow out back into the atmosphere!I'd suggest pulling the air into an airconditioned room (dry air), then HEPA into you clean igloo tent. But chances of it working is maybe 10% at best with platter alignment, embedded sector mapping, thermal expansin factors and a nunmber of other variables.3)Your one remaining drive hashalfof the data (the second drive has the other half), and the third has redundancy data to reconstruct either half....not a happy place.I'd take the drives as a complete untouched set to Dr Disk and cross my fingers as well as mybank account.Don't spin them up any morein case there is any metal flying around inside the disk cavity!

author: Mechanical Menace
author_rank: Super Contributor
timestamp: August 01, 2015, 03:03:08 am
content: This why I don't use RAID5 or RAIDZ1 anywhere...All I can say is what have you got to lose? It works with lower density drives if you're careful, should work here at least for long enough to get the data off. Hope you have a steady hand though.

author: pickle9000
author_rank: Super Contributor
timestamp: August 01, 2015, 03:40:10 am
content: When you say change the platters do you mean to swap the pcb to one of the faulty units and then do your backup?I would maintain the seals and try the pcb swap first.If you do plan to open the cover you can make a white box (large plastic container cut up), sheet of glass a hepa filter, anti static mat and surgical gloves. Liquid rosin on a lint free cloth (tac cloth) to wipe everything down inside the box.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 03:48:31 am
content: Quote from: SL4P on August 01, 2015, 03:00:36 am1) I don't think it will matter. If the same data is at the same sector number (LBA) on both drives (even though the Toshiba has MORE sectors) it should still work when restarted.2) no, I mean blowing outward (positive pressure - HEPA on the inflow air) (not sucking inward over the drives). I think we both mean the same thing.3) Your one remaining drive has half of the data (the second drive has the other half): that's an interesting way to look at it, and is a good argument for mirror only. I'm considering reconstructing it as a mirrored server now, actually. or a RAID10 with 4 drives.It's not worth it to me to go to a repair service. I've already decided that if I lose the remaining data, it will not be the end of the world. It's a personal loss, representing years of work, more than anything else. 15 Years of scanned personal documents, (tax data, tax returns, retirement savings, etc), my family photos (scanned from print or slides), approx. 600GB of datasheets, scanned my bookshelfs, ISO copies of my subscription CD's which I don't have anymore, my online books and magazines collection, DVD and music CD collections.. etc.Nothing earth shattering, nothing that absolutely needed to be backed up except my personal documents, which is where I failed myself the most for not backing that stuff up earlier. Everything else can (almost) be recovered from other sources.

author: SL4P
author_rank: Super Contributor
timestamp: August 01, 2015, 03:52:56 am
content: I feel for you - I had a similar event about a year ago - RAID5 across three drives - one went down, followed by the second.Luckily I had a reasonable backup strategy (raw to DVD), but the online backup SW I was using was proprietary / encrypted bydefault- so I lost about 15 months of stuff. Some irreplaceable - sigh.Good luck!

author: helius
author_rank: Super Contributor
timestamp: August 01, 2015, 03:53:35 am
content: Be careful with alignment... When you loosen the screws holding the platters to their hub, you may discover that there is nothing keeping them rotationally aligned. It might be worth making a jig to hold the platters during the time they are off the hub.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 03:54:00 am
content: Quote from: pickle9000 on August 01, 2015, 03:40:10 amno, not just a pcb swap, although I can try that first with the known good one. Do I need to swap the serial EEPROM along with it? I think so.However, I don't think swapping the PCB will solve it. It seems more like trouble reading from the platter, and I suspect it's a head failure.QuoteYes, like this, to open it up in a makeshift clean-hood with HEPA filter and positive pressure airflow, to open the drive and swap the physical platters onto the known good one.The wipe down with liquid rosin is a good idea.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 03:59:49 am
content: Quote from: helius on August 01, 2015, 03:53:35 amSeriously? don't they have pins or screw holes to line them up? a few microns out and they may not workUnless you mean just within the relative alignment (like finding hole #1 on both platters of the 6 screw holes in the spindle)

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 04:01:50 am
content: I'm mostly worried about shaky hands and causing head damage on the good drive. Drives these days have really fragile heads.And I'm good that I DO NOT have shaky handsbut still, all it takes is one slip..

author: Psi
author_rank: Super Contributor
timestamp: August 01, 2015, 04:14:57 am
content: I've never seen anyone successfully recover a HDD by swapping either the PCB or the platters with a good drive.It probably depends on the brand, some might work, but i think most drives have their low level configuration split between flash memory on the PCB and data on the platters.So swapping things around just corrupts stuff. I can see it working if the motor is dead though, (swapping both the pcb and platters).Does the drive only start clicking when you read data from it? ie, when you start copying some file/folder. Or does it click pretty much as soon as you power it on?If they only start doing the click click click when you read something then there is a chance they can be recovered.First i would figure out what folder /file is causing the click click click by a few trial an error copes of folders. eg, get off whatever data you can first. If the drive is part of a raid you probably cant do this. Since it has to be mounted as the whole raid volume the controller will keep dumping it from the raid as soon is you add it. So move to the next step..Run Spinrite on the drive/drivesSpinrite does a think called dynostat recovery which disables SMART and then tries to read the bad sector many times by instructing the drive to read some other random data on the disk and then to read the bad area in raw mode.The result is the head coming at the bad sector from different directions and with repeated attempts from slightly different alignments as well.With many iterations it will build up an average value for each bit in the bad area until it finds combination that passes the drives checksum with a good probability. At that point it re enables SMART and writes back the correct data to the bad sector. Since the drive will have this sector marked as 'reallocation pending' as soon as it sees a write it reallocates that sector somewhere good.I've had good success using spinrite to fix drives that start clicking when a file/folder is accessed.There was a time when there was good money to be made buying dead Ipod classic's from ebay (the type that have a real HDD inside). All they needed was a spinrite run on them and they were good to go.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 04:23:34 am
content: They can't be accessed anymore for any kind of sector copying (or spinrite).They both now spin up when power is applied, click 2 or 3 times (I can't remember .. I think it's 3 clicks) then the motor shuts down and it never reports itself as being available to the BIOS. So the drive does not report any READY status.Googling for this and reading forums seems to tell me two things1) the drive can't read the firmware track, so it can't boot2) or, the remapped sector counter is full, so the drive won't start up.For #2, there are some serial port commands to send to the drive to clear the smart data, and it can possibly be booted up in a bad state, but likely able to read some data. I have not been able to find the proper serial port commands for a 7200.14 drive.Also, I think I need to first hook up the serial port to the drive and watch the embedded boot, and see if it reports anything.I'll do that first and copy it to here if anyone's interested.

author: pickle9000
author_rank: Super Contributor
timestamp: August 01, 2015, 04:43:54 am
content: I have done board swaps on older drives (500gig and smaller) successfully but only for data recovery and not all where a success. I think that platter removal would be a fail. Even keyed the tolerances are way too small, do it last.

author: SeanB
author_rank: Super Contributor
timestamp: August 01, 2015, 04:59:47 am
content: New drives are not going to survive the swap, as the alignment is critical, you need to align the whole stack to within 1nm, which is the data track width. In the factory this is done with a machine that moves the heads from the top through a hole in the case ( those little covers on the case) and writes the alignment data onto the clamped stack of disk platters. Loosen the bolts and tighten them again without doing anything will destroy this, just from the metal relaxing.Try doing the controller swap and swap the eprom on the controller, which stores the head alignment info for the drive, and how it is aligned inside.It will be the only thing you can do, other than sit with an electron microscope to read the magnetic data off the platters bit by bit.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 05:13:38 am
content: Quote from: SeanB on August 01, 2015, 04:59:47 amThis is the information that decides it for me. Thanks. Not gonna waste my time then. Yes, now I seem to recall Free Electon wrote about this alignment procedure too, that's done from the taped hole on the side of the disk drive.Quoteok. I think I'll first try to get the serial port wired up and capture the boot log, then maybe there's some serial port commands I can do.if swapping the platters is going to be a problem, perhaps I can swap the head stack? i.e leave the platter in the bad disk screwed down, but swap the good heads and the good controller (and the EEPROM from the bad controller) and maybe that will have better luck? Yes, I know the heads areREALLYdelicate and fragile and cannot bounce or touch together, they will be destroyed. I opted for a platter swap first because I know a head swap is much harder.But if you think that a platter swap is almost guaranteed NOT to work, then I'll start with a head swap.And it's almost an exercise to see if it will work, simply because I'm ready to lose the data, but would like to try to save it still.Thanks for all the suggestions so far.

author: Psi
author_rank: Super Contributor
timestamp: August 01, 2015, 05:43:31 am
content: Quote from: SeanB on August 01, 2015, 04:59:47 amModern drives have data packed so dense that the data is read as the head moves over (and past) the track it's looking for. The head doesn't simply move to track X, stop and read the data because there's not enough resolution in the head control DAC by an order of magnitude or two.Old hdds and floppy disks used to seek to a specific track. They had a stepper motors to control the head whereas modern drives do head control using a electromagnet allowing them to move position with infinite steps but not much absolute accuracy.So the drive should be able to tolerate platter alignment. It has to home-in on the track anyway so it shouldn't matter where it is.Atleast, this is how i was told they work.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 05:57:43 am
content: Quote from: Psi on August 01, 2015, 05:43:31 amIn your dreams. Even those who professionally recover the data have a very big trouble to move the platters, even with special tools. I'm not even sure is this is possible at all with newest HDDs, though could be done about 10-7 years ago but not at home.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 06:05:11 am
content: At best head block could be tried to be replaced and work afterwards, but no way platters.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 06:06:11 am
content: So given that the heads do not move with absolute accuracy, but the platters MUST be aligned, do you guys think it would tolerate a head swap better?

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 06:07:13 am
content: Quote from: wraper on August 01, 2015, 06:05:11 amHa. you answered my question while I was typing it.All in all it's going to be a learning experience. I'll keep the thread informed.

author: amyk
author_rank: Super Contributor
timestamp: August 01, 2015, 06:12:14 am
content: Yes, a head swap would have much better chances, although the chances are still quite small...The problem isn't with rotational alignment as there is no "index position" (sector numbers are encoded along with data), but with radial alignment (runout). The head servo can track runout to a certain extent, but too far and it won't be able to follow the track.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 06:36:46 am
content: And this was made with 750 GB HDD.QuoteQuote

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 01, 2015, 06:41:37 am
content: Swapping platters is way beyond anything that could be considered remotely promising.Even if you could get the proper clean environment (which seems VERY doubtful) and get the platter(s) into proper mechanical alignment, I strongly suspect that the tracks are self-aligned (i.e. the tracks are defined by the actual heads in the drive and not to some "standard". So swapping platters into a different drive may never "align" with the receiving head stack.Swapping boards seems like the only kind of field-procedure that has any kind of reasonable expectation of success. And even that method may be less promising with newer drive technology where so many factors are firmware and saved in NVRAM.If the data is really valuable, I would send it off to a professional recovery company who know how to do it right. This hardly seems like DIY territory if you at all serious about actually recovering the data.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 07:12:10 am
content: It's not valuable which is why I'm willing to try to DIY it. Just enough to get it to run for about 4 hours so I can image the drive, that's my goal.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 07:12:49 am
content: Quote from: Richard Crowley on August 01, 2015, 06:41:37 amThat's actually true. AFAIK, when swapping heads, multiple donor HDDs can be scrapped just to find the head block which is closest by it's parameters to the faulty one.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 07:16:55 am
content: Quote from: codeboy2k on August 01, 2015, 07:12:10 amMay sound like your expectations are small. But actually is quiet a lot to expect from HDD which was opened and even more if something was replaced.

author: AndyC_772
author_rank: Super Contributor
timestamp: August 01, 2015, 07:33:33 am
content: I vote that a year from now, the cost of having used a professional data recovery service won't seem so bad, and it'll have been worth it.Two discs failing so close together... damn, I feel for you. Who'd have thought any product could be made so consistently?

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 08:07:29 am
content: Quote from: AndyC_772 on August 01, 2015, 07:33:33 amSeagate is very consistent... in failing HDDshttps://www.backblaze.com/blog/3tb-hard-drive-failure/QuoteQuoteNow look at the deployed graph. Very similar to the failed graph. Seems they live exactly the same time and go kaput.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 08:11:41 am
content: re: the backblaze report: That 3TB drive is the same as my 2TB drives, the 7200.14 series.and mine was deployed Nov 2012. And also failed in Q3 2015. Go figure.Quote from: wraper on August 01, 2015, 08:07:29 amI've had previous failures with seagate too. And I've had good luck with Western Digital, but I've had those fail before, so it's not one vs. the other.I think that todays higher density HDDs are just too tightly packed bits on the platters now, and that's very difficult to read back consistently, The drives have to go through hoops to get a good read, and the heads are getting smaller and smaller too. It's bound to fail, and it's also evidenced by the fact that the common disk drive warranty is only 1 year now.This time around I thought I would try Toshiba, which I believe to be Fujitsu. Fujitsu has had a great hard drive division, I remember big Fujitsu removable packs back in the 80's, so they are one of the early pioneers of the technology.I do think I need to buy 2 more drives and run them in RAID10 or RAIDZ2 this time around. RAIDZ1 seems risky now.

author: PlainName
author_rank: Super Contributor
timestamp: August 01, 2015, 09:16:16 am
content: QuoteI think you should forget RAID. It's purpose is not as a backup (or to do away with backups) but just to remove the downtime associated with failed media. That is, RAID will warn you the data is at risk and allow you to replace bust media without losing access (temporarily!) to that data.What it won't do is protect you from disasters. That power surge that takes out the entire rack, finger trouble, rats, etc. RAID does nothing for those, so you still need to have a coherent backup strategy AS WELL as running RAID. So why bother?Since you must have the backup anyway, all you're really interested in is circumventing the several hours of downtime whilst you restore from backup (plus the time taken to acquire new media). For that, a mirror is pretty good. There is a low risk that bother drives will fail as you're dealing with a problem, but that will screw your bigger and better RAID too, as you found.Instead of shoving two more drives in that RAID array, and hope no real disaster occurs, just use them as two backup sets, alternating them and/or preferentially keeping one off-site. Just not having one plugged into a live PC will make your data MUCH safer.

author: Psi
author_rank: Super Contributor
timestamp: August 01, 2015, 10:19:11 am
content: Hot swap raid mirror systems are useful for backups. Especially the all-in-one caddie versions that have a built in controller. They have one sata port so appear to the OS as a single drive.They usually have 3 drives, 2 of which are kept in mirror and 1 is a hot spare.At any time you can turn the key, pull out a drive and take it with you as a backup, the hot spare then kicks in.I know a few companies that use this quite a lot. They unplug a drive every night as a take home backup and then plug it back in the next morning.

author: george graves
author_rank: Super Contributor
timestamp: August 01, 2015, 10:39:09 am
content: Quote from: Psi on August 01, 2015, 04:14:57 amDon't get me started on Spinrite - I'm convinced it doesn't work. Steve Gibson is a really smart guy, and I bet back when he came up with the software (1980's) if worked 50% of the time when drives had the aerial density of a the hindenburg - but nope - I've tried it on about 25 drives I'd say - at least 20. I've never recovered a drive with it - ever - not even a single file.Anyways, he still pushed his software on Leo Laport's "TWIT" shows. Kinda shamelessly for a product that doesn't work. But he swears it does!

author: PlainName
author_rank: Super Contributor
timestamp: August 01, 2015, 11:17:24 am
content: QuoteSounds like I should have one or more of thoseAlso sounds like it's going to be expensive

author: Psi
author_rank: Super Contributor
timestamp: August 01, 2015, 11:23:16 am
content: It has worked numerous times for me on drives with read errors.It doesn't work if the drive is dead (obviously) or if the reallocation pool is full or if there's a hardware fault.I've had it churning away on bad areas of many disks. Running dynostat for sometimes as long as a couple of days on end.On most disks it eventually gets the bad areas reallocated with data intact.Don't get more wrong, i'm not saying it works all the time, but it has definitely worked for me most of the time when dealing with drives with read errors. Where the drive keeps locking up or returning CRC/IO error when you tried to access a particular file/folder

author: Psi
author_rank: Super Contributor
timestamp: August 01, 2015, 11:27:16 am
content: Quote from: dunkemhigh on August 01, 2015, 11:17:24 amI don't think it was ridiculously expensive. i remember the brand of one i used to work with. It was called accusys.

author: amyk
author_rank: Super Contributor
timestamp: August 01, 2015, 02:13:02 pm
content: Quote from: Richard Crowley on August 01, 2015, 06:41:37 amIndeed there is a lot of "adaptive parameters" as they're called, stored off the platters and different for each head stack. This is usually in an EEPROM on the board but I think I read somewhere that some models have that data stored as part of the head preamp.But beyond that and platter runout, head alignment in modern drives is not such an issue as they're designed so the heads will find the right sectors as long as it can read them. The fact that thermal expansion will significantly change the absolute positions of tracks means that no fixed track positioning can be used, they just use the embedded servo info to find where the tracks are:http://hddscan.com/doc/HDD_Tracks_and_Zones.html

author: PlainName
author_rank: Super Contributor
timestamp: August 01, 2015, 04:09:49 pm
content: QuoteThanks. I had a look at their webby and, ignoring the full size rack stuff (!) I think we'd be looking at around $2k. Not that bad, but far too expensive.One of my requirements is that whatever I use is common and cheap. If I use $2K worth of kit then should it go titsup I will be stiffed with a $2K bill to get back to where I was, and I don't have a choice of whether to pay it or not. Further, and I've been hit a few times with this, the probability is that just when I need it most (i.e. to replace blown kit) it turns out they stopped making them the year before and they're like pixiedust.For a non-critical system, a proprietary $2K thing is fine, but not for looking after my data. Against that, if the take-away drive is essentially a bootable, readable drive on any old disk controller, that mitigates the problem alotso I could still be tempted

author: retiredcaps
author_rank: Super Contributor
timestamp: August 01, 2015, 04:31:58 pm
content: Quote from: codeboy2k on August 01, 2015, 08:11:41 amI wondering if all these Seagate failures is related to the floods in Thailand back in Nov 2011 which affected the hard disk industry?http://www.theverge.com/2011/11/23/2582677/thailand-flood-seagate-hard-drive-shortageMaybe Seagate bought less than prime parts and/or the switch to higher density disk was released before it was fully tested?"And while manufacturers are adapting to the shortage by including fewer parts in their drives by using a single higher-density disk with two heads instead of two disks with four heads, Luczo says price increases are inevitable."

author: nctnico
author_rank: Super Contributor
timestamp: August 01, 2015, 04:41:18 pm
content: Quote from: codeboy2k on August 01, 2015, 08:11:41 amIn my experience the biggest enemy of a hard drive is heat. Remember hard drives have been on the edge of technology for decades due to strong competition. If you keep a hard drive cooled properly (lots of airflow) you can easely get a decade out of it. However a lot of computer cases offer zero airflow to the hard drive bays and that could make a drive fail within a year. If a hard drive doesn't need to be fast you can also consider using Western Digital's green series. These use less power (rotate at 5400rpm) and therefore aren't thermally stressed like higher performance drives.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 04:43:39 pm
content: Quote from: retiredcaps on August 01, 2015, 04:31:58 pmThey made a lot of shite drives even without floods, like famous 7200.11 series(have a few laying around, full of bad sectors).Edit:Nope, those are 7200.12, still shite. Edit2: turns out I have both dead 7200.11 and 7200.12 HDDsIf looking on the past 7 years, overall they took a huge leadership in making the least reliable drives out of all manufacturers.One more graph from backblaze:Quote

author: Mechanical Menace
author_rank: Super Contributor
timestamp: August 01, 2015, 04:47:54 pm
content: Quote from: nctnico on August 01, 2015, 04:41:18 pmIn my experience it's a dodgy power supply in one way or another. For some reason where I live is prone to sags and swells. Until I built myself a UPS of sorts my PC was resetting itself a couple of times a day through to them and I was going through a HDD every 6 months.

author: sync
author_rank: Frequent Contributor
timestamp: August 01, 2015, 04:55:28 pm
content: Quote from: Mechanical Menace on August 01, 2015, 04:47:54 pmIn my experience it's cheapness. Server hard drives last much longer. And heat is also an enemy.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 06:38:58 pm
content: Quote from: dunkemhigh on August 01, 2015, 09:16:16 amI think I will follow this advice, and use a mirror when I rebuild it, instead of RAIDZ (which is a RAID5 workalike)I like the idea of an external hotswap disk, so that I can just use the mirroring itself to make a backup. I can hotswap two or more to keep one live for performance and one backup out of the PC. I can buy more in the future and rotate them.With a system like that in place I might have been more diligent about the backupsAs it turned out, I had TB's of RAID and no good way to back it up, so I got lazy and didn't do it before the inevitable failure.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 06:55:22 pm
content: Quote from: sync on August 01, 2015, 04:55:28 pmI don't know if heat was a factor here. All three drives were in a small mini-atx case, but spaced well apart (about 5cm between each drive) and there was decent airflow.The last available SMART data that I have for the drive just before it failed shows the max temperature at 45C . No drive was above 45C in the max temp column, and I don't think 45C is too hot for a drive. Maybe it was ?I was running SMART daily short offline tests, and weekly long tests via cron. SMART logs showed these tests always passed, except the one drive that failed first started to show short test failures at 90% complete then failed within 2 days after that. The second drive to fail never had any errors in the SMART log, except its reallocated sector count was increasing over the years. It always seemed like normal to me, given that it was a high-density 2TB drive, I expected some reallocated sectors to be normal. At the time of the second drive failure, there was 382 pending reallocated sectors (which doesn't seem too high). It just outright failed while running in the degraded RAID. The second drive never failed any SMART offline tests, long or short.Finally, being ZFS, I was also running a weekly data scrub (which, for non ZFS aware people, means that it reads back all the data, verifies all data on the members of the RAID array, and rewrites and logs errors). That weekly scrub log NEVER showed any errors ever being repaired.Overall, I'm pretty disappointed in this experience with RAID, but it's not the end of the world for me. Just more of a personal feeling of loss more than anything else. And I'll rebuild it with a mirror set next time and a clear backup strategy using hot swap drives.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 07:03:36 pm
content: Quote from: Mechanical Menace on August 01, 2015, 04:47:54 pmTwice In the past I've had a power outage take out a desktop drive. This was back when 30GB was the normal desktop drive sizeUsually that happened when the grid browns-out or flicks off then on again really quickly (is that a grid switch? I think so).We were also experiencing quite a few power failures here, especially during the winter storms. So I put in a UPS on every desktop and on the server, and they've saved me countless times already. This RAID server at the topic of this thread was on a UPS.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 07:18:36 pm
content: Quote from: codeboy2k on August 01, 2015, 06:55:22 pmNormal HDDs don't have growing reallocated sector count. It means that HDD is crap and data from those sectors most likely was corrupted. For example, I have 1TB WD green with 38 000 hours power on time, 2 TB WD green with 22 000 hours, 3TB toshiba 4800 hours. All of them have zero reallocated sector count.QuoteThis means almost dead HDD

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 07:47:19 pm
content: Quote from: wraper on August 01, 2015, 07:18:36 pmThat's clear nowThere is lots of misinformation on the net regarding reallocated sector counts. It really is normal for large TB disks to have some reallocated sectors, in my opinion it's inevitable. I think I might have dropped the ball when it started growing over the years. There was a huge growth at the beginning when it was first installed, and then it was stable for a few years, but recently would add one or two more sectors every month or two.There was no big red banner saying "CHANGE YOUR DRIVE NOW, DUFUS!" -- maybe there should be.Also of note was that the first drive to fail had no such reallocated sectors, and only recently started to fail the short offline SMART test, and then failed completely 2 days after that. The second drive did have the reallocated sectors already, but has never failed any offline tests, and also failed 24 hours after the first drive. The third drive of the RAID set currently has no reallocated sectors and has never failed the SMART offline tests.All of which tells me there is no good indicator of pending drive failure.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: August 01, 2015, 07:50:19 pm
content: Quote from: wraper on August 01, 2015, 07:18:36 pmThat Toshiba is half way through it's life span if my experiences are at all common.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 07:57:57 pm
content: Quote from: Mechanical Menace on August 01, 2015, 07:50:19 pmI sure hope not ..I just bought 2 new Toshiba 2TB drives to replace the 2 dead Seagates. And based on my own 2 out of 3 failed in 2.5 yrs, and 43% of Backblazes's Seagates failed in 2.5 years, I am having my doubts about the last remaining Seagate that I own, and I just want to toss it out the door and get another disk. Maybe my 3rd and 4th disk should be a different brand.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 08:24:23 pm
content: Quote from: Mechanical Menace on August 01, 2015, 07:50:19 pmthis is Toshiba DT01ACA300 aka rebadged Hitachi HDS723030BLE640 which proved to be quiet reliable.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: August 01, 2015, 08:26:09 pm
content: Quote from: codeboy2k on August 01, 2015, 07:57:57 pmMaybe I've just had a bad experience with them. They were identical drives bought at the same time so likely, and I wasn't sold them as Toshiba either. They were Toshiba drives in some German company I've never heard of boxes, which I was sold as Hitachi's but couldn't get my money back.Quote from: wraper on August 01, 2015, 08:24:23 pmExplains the circumstances of me receiving them. Mine were the DT01ACA100if that makes much of a difference.EDIT:Nope it was the 300, was reading the wrong part of the label lol. Says it was from April 13.

author: wraper
author_rank: Unknown
timestamp: August 01, 2015, 08:27:05 pm
content: Quote from: codeboy2k on August 01, 2015, 07:47:19 pmAs much as I have read, growing reallocated sectors from the very beginning is quiet specific for Seagate, which is one more reason to not buy them.

author: PlainName
author_rank: Super Contributor
timestamp: August 01, 2015, 08:47:46 pm
content: QuoteA bad move, IMO. When I set up a mirror I always use different manufacturers. Doesn't matter if one of them has a bad rep - you're planning for a fail and if it fails way before the other drive that's good! Just so long as the fail cycles don't get in sync...

author: madires
author_rank: Super Contributor
timestamp: August 01, 2015, 08:53:54 pm
content: Please use server/RAID disks for servers and not desktop disks! Desktop disks are not designed to run 24x7 with a typical server usage profile.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 10:29:31 pm
content: Quote from: dunkemhigh on August 01, 2015, 08:47:46 pm... as two of my 3 Seagates did ! (all bought at the same time)I have already bought 2 Hitachi drives DT01ACA200. I think I will add to this 2 more WD drives and split them across a RAID10, with 1 Hitachi drive mirroring a WD drive, then striping across 2 mirror sets like that. If both Hitachis fail at the same time, I still have 2 WD in the stripe.POOL============================ ===========[ WD ] [ Hit ] [ WD ] [ Hit ]Quote from: madires on August 01, 2015, 08:53:54 pmIt's my home server. It's lightly used, and runs 24x7 just like my desktop. By no means is it seeing a typical corporate server usage profile, and desktop drives are fine. I just need to properly plan for failure.

author: sync
author_rank: Frequent Contributor
timestamp: August 01, 2015, 11:27:23 pm
content: Quote from: codeboy2k on August 01, 2015, 07:47:19 pmA new disk has 0 reallocated sectors reported via SMART. The factory defect sectors are not shown. A few grown reallocated sectors are not a problem. It can happen. But they should not constantly growing. I would not trust a disk which has more than 10-20 reallocated sectors (after a few years).This is a 4 years old 1TB hard drive (WD10EARS) from my XBMC PC:1 Raw_Read_Error_Rate 0x002f 200 200 051 Pre-fail Always - 03 Spin_Up_Time 0x0027 189 183 021 Pre-fail Always - 65334 Start_Stop_Count 0x0032 098 098 000 Old_age Always - 25825 Reallocated_Sector_Ct 0x0033 199 199 140 Pre-fail Always - 17 Seek_Error_Rate 0x002e 200 200 000 Old_age Always - 09 Power_On_Hours 0x0032 094 094 000 Old_age Always - 443310 Spin_Retry_Count 0x0032 100 100 000 Old_age Always - 011 Calibration_Retry_Count 0x0032 100 100 000 Old_age Always - 012 Power_Cycle_Count 0x0032 098 098 000 Old_age Always - 2581192 Power-Off_Retract_Count 0x0032 200 200 000 Old_age Always - 61193 Load_Cycle_Count 0x0032 075 075 000 Old_age Always - 375033194 Temperature_Celsius 0x0022 114 098 000 Old_age Always - 33196 Reallocated_Event_Count 0x0032 199 199 000 Old_age Always - 1197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 14198 Offline_Uncorrectable 0x0030 200 200 000 Old_age Offline - 7199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0200 Multi_Zone_Error_Rate 0x0008 200 200 000 Old_age Offline - 21Only one reallocated sector but 7 Offline Uncorrectable ones :-(btw: I try to keep the disks in servers/RAID systems under 30°C. Which is usually not a problem with well designed rack mount servers and cooled server rooms. Not easy at home of course.And as madires said, use server disk for anything which runs 24/7 or the data is important. Enterprise 7200rpm SATA disks are affordable.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 01, 2015, 11:54:51 pm
content: Quote from: sync on August 01, 2015, 11:27:23 pmReally so low? If that's the case, then I'll need to change my thinking. I'm a techie, I have never been an enterprise server admin, so I don't have any first-hand experience with disk drive statistics or when to know when it's going bad. You say 20 sectors on a 2TB disk that reports about 3907029168 sectors (512B/sector), but is only 0.5 ppm or 500ppb. It's really, really, small to be throwing the disk out, isn't it ?QuoteI'm going to rebuild this server with a mix of the 2 x 2TB Hitachi's that I already bought and 2 more 2TB WD red's these are $119 and I agree are affordable.For future backup, I've decided to get a used LTO3 drive from eBay. LTO3 tapes are cheaper and more space efficient than buying more disk, and if I grow the server I just need to add more tape. Plus tape allows me to get a real monthly/weekly/daily strategy going without a lot of cost.I'll try to rebuild the lost RAID offline after I get this server back up with all new drives.

author: wraper
author_rank: Unknown
timestamp: August 02, 2015, 12:17:19 am
content: Quote from: codeboy2k on August 01, 2015, 11:54:51 pmHow much worth is in the HDD which corrupts data may I ask? Reallocated sector = sector was remapped because data couldn't be read from it = your data were corrupted. Now let's imagine, your HDD is full of HD video, each file like a 40-50 GB. Now take your 0.5ppm of corruption figure and suddenly it appears that you don't have even a single file unaffected and all of them were corrupted.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 02, 2015, 12:29:55 am
content: Quote from: wraper on August 01, 2015, 08:24:23 pmI did some googling, and it would seem that it's also the IBM Deskstar 7K3000. Reviewers say it's a 5-platter drive, which would account for it's reliability. Most 3TB drives are 3 or 2 platters these days, which means the bits are denser and harder to read, so it can fail more easily. That's going to be my opinion going forward from now on.I was originally going to do a RAID10 with a mix of 2TB Hitachi and 2TB WD red's (4TB total) but I think I'll change my mind now, and simply do a 2 disk mirror of 1 2TB Toshiba/Hitachi DT01ACA200 and 1 2TB WD red. (for 2 TB total). It's slightly cheaper per TB ($86 per TB vs $100 / TB), uses less power than 4 drives, and good enough for me right now as I don't have the data anymore to need more than 2 TB storage.And if I'm thinking of LTO3 tape backup, do I even need to mirror it anymore? Why not just stripe it for 4 TB total and rely on (tested!) backups then. It's my home server, I really don't NEED the reliability of RAID, I realize that now. What I need, going forward, is good backups.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 02, 2015, 12:33:56 am
content: Quote from: wraper on August 02, 2015, 12:17:19 amIt's just my home data. No business data, and nothing that I can't do without right now, which is why I'm not rushing the disk to an $800 data recovery service.What I will do is rebuild the server, get a good backup system in place, and go forward. The lost data on my existing RAID I'll keep those disks separate and offline, and try to recover any data just as a learning exercise.

author: wraper
author_rank: Unknown
timestamp: August 02, 2015, 12:46:56 am
content: Home or business data. What is the value of the medium if it does not serve it's main purpose - store the data intact. Imagine some firmware with 0.5 ppm of data corrupted. like a single byte corrupted in 2 MB of flash ROM. Your device becomes useless junk.http://www.trademe.co.nz/Browse/Listing.aspx?id=925187196Quote

author: TerraHertz
author_rank: Super Contributor
timestamp: August 02, 2015, 03:25:10 am
content: I've completely given up on RAID systems.* They add complexity in setup and management,* Add an extra critical failure point - the RAID system hardware itself. If that fails the drives are typically unreadable via other means, and trying to replace the failed board or whatever can be hard &/or expensive.* You typically can't just pull a drive out and read or copy it using standard hardware.The simple rule I follow now is, can I read the drive in a cheap external USB HDD dock? Can I do complete file system duplications using treecopy utilities that copy all files without corrupting attributes like file dates, and will run to completion without throwing millions of errors and stopping without being restartable?I won't use any system that doesn't allow that.I keep all 'work' drives in removable trays, and never ever mix system/utility installs with work spaces.With that, I can manage work backups as appropriate, using any old excess/found/salvaged drives or USB sticks (free), and all of the backup devices are readable as standard file systems on any PC. Such backups can take a long time, but I can run them on any spare PC without tying up my main work system.Also when possible I format backup drives as FAT32, since as a last resort I can manually examine and patch FAT32, but NTFS is completely beyond such measures. For me, anyway. It sucks that now almost always filesets are too big for FAT32 drives.Incidentally, many years ago, maybe around 2004, I tried a HD PCB & platter swap. The drive contents was fairly important. I'd decided a backup was way overdue, and was spending a few hours doing folder tree structure tidying, before backing up. Ha ha, big mistake inviting Mr Murphy to lunch. During that process the drive suddenly became a non-drive, ie not recognized by the BIOS at all, suggesting PCB failure. I had an identical working blank drive. Not sure if removing the PCB might break hermetic seal of the interior, I improvised a 'clean area' by using a large clear plastic bag, new from a stack and never 'fluffed up', so hopefully the interior was dust free. Cleaned the two drive exteriors with compressed air, slipped them and a screwdriver into the bag, taped surgical gloves onto the bag opening, and swapped the good PCB onto the bad drive. Result: now it was recognized, but couldn't read any data. I then tried a platter swap, so the single precious platter was in the body with known good PCB, heads and head-amp. That wasn't readable either.On inquiring, I was told that (even then) the boards had head tracking calibration data in flash, and board or platter swaps never worked anymore. Never did recover the lost files.

author: Halcyon
author_rank: Unknown
timestamp: August 02, 2015, 06:12:43 am
content: Quote from: Psi on August 01, 2015, 04:14:57 amWe do just this at work when other methods fail. We use a "donor drive" to swap the PCB out of. But it doesn't always work (even minor differences in drive firmware is sometimes enough for it to fail). If we get really desperate, the drive gets sent off to another Government lab with lots of cool and expensive toys. :-)Having lost data myself without a proper backup routine in place (not due to drive failure, but I locked myself out of the encrypted drive as the password was stored in a KeePass file inside the encrypted volume, do'h! Catch 22). Ever since, I back everything up to disk and LTO tape.

author: sync
author_rank: Frequent Contributor
timestamp: August 02, 2015, 12:31:16 pm
content: Quote from: codeboy2k on August 01, 2015, 11:54:51 pmYes, really so low. Also this is for a desktop PC like case. On an enterprise server I didn't care. It's the RAID controller's job. Don't think in relative terms like ppm here. Every reallocated sector is a little fault. Would you trust a device which is constantly getting new faults?QuoteLTO is a nice technology. But tapes have also a few drawbacks. First I'm skeptical about used tape drives from ebay. Tape drives will wear out. They are delicate precision mechanically devices. They should be used in a dust free environment. They want a minimum sustained data rate or it stop, reverse a bit and start again repeatably (shoe-shining). This will wear out the drives and tapes fast. Also this reduces the usable capacity. Depending on the LTO-3 drive at leased 60 or 70MB/s sustained data rate is need. Better double for compression.The capacity of a LTO-3 tape is 400GB, compressed up to 800GB. You are taking about a few TB of storage. If you want to backup that you need a lot of tapes. Which means swapping tapes over hours for a full backup.QuoteGood luck with that.

author: senso
author_rank: Frequent Contributor
timestamp: August 02, 2015, 12:42:06 pm
content: Quote from: Psi on August 01, 2015, 04:14:57 amDone that, successfully, just remember to also swap the SOIC-8 EEPROM and its all good(when its a pcb related damage, in the case, it was a grilled motor driver).

author: Psi
author_rank: Super Contributor
timestamp: August 02, 2015, 12:59:25 pm
content: Here's my oldest drive that's still in use, happens to be a seagate (before they got shit).It's in my server and has been running 24/7 for 87998 hours... 10 years!!!It's seen entire generations of other seagate models (1.5 and 3TB) get designed, manufactured, and then die.And it still doesn't have any reallocations or even any pending reallocations.=== START OF INFORMATION SECTION ===Model Family: Seagate Barracuda 7200.8Device Model: ST3200826ASerial Number: 3ND0HW6YFirmware Version: 3.02User Capacity: 200,049,647,616 bytes [200 GB]Vendor Specific SMART Attributes with Thresholds:ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE1 Raw_Read_Error_Rate 0x000f 052 048 006 Pre-fail Always - 785304783 Spin_Up_Time 0x0003 098 098 000 Pre-fail Always - 04 Start_Stop_Count 0x0032 100 100 020 Old_age Always - 4215 Reallocated_Sector_Ct 0x0033 100 100 036 Pre-fail Always - 07 Seek_Error_Rate 0x000f 064 060 030 Pre-fail Always - 28106459 Power_On_Hours 0x0032 001 001 000 Old_age Always - 8799810 Spin_Retry_Count 0x0013 100 100 097 Pre-fail Always - 012 Power_Cycle_Count 0x0032 100 100 020 Old_age Always - 511194 Temperature_Celsius 0x0022 029 045 000 Old_age Always - 29 (0 14 0 0 0)195 Hardware_ECC_Recovered 0x001a 052 047 000 Old_age Always - 78530478197 Current_Pending_Sector 0x0012 100 100 000 Old_age Always - 0198 Offline_Uncorrectable 0x0010 100 100 000 Old_age Offline - 0199 UDMA_CRC_Error_Count 0x003e 200 200 000 Old_age Always - 3200 Multi_Zone_Error_Rate 0x0000 100 253 000 Old_age Offline - 0202 Data_Address_Mark_Errs 0x0032 100 253 000 Old_age Always - 0

author: SeanB
author_rank: Super Contributor
timestamp: August 02, 2015, 01:09:39 pm
content: I did it with a 20G Seagate, luckily I had bought a few of the same model drive at the time ( same size Seagate, and the donor was a very close firmware revision drive), though the temporary donor machine was taken off of a very unhappy data capture clerk for a 2 day period, as her machine was the closest match. Got the 10G of data I needed and the OS cloned to another ( slightly newer but still used) drive, before I swapped controllers again to return the machine. cloned the drive again so I would have a spare, as the software is no longer obtainable, but is happy to run with a dongle only. Finally retired the Win95 machine last year, as the PBX it ran was replaced with a newer system. Still have it, and it still works, though I would not want to use IE4 again on the internet, and it is only a 90MHz Pentium processor. I kept it running using the pile of old scrapped slowpoke machines over the years, upgrading RAM to 512M as I got the modules as opposed to the 64M it originally had.Still have a pile of 32M, 64M, 128M SIMM's around in a baggie, I used a few in printer upgrades, where they fitted older HP printers. Some went to being able to print a full page graphic from the old RAM printing a quarter page at a time.

author: SeanB
author_rank: Super Contributor
timestamp: August 02, 2015, 01:16:04 pm
content: Quote from: Psi on August 02, 2015, 12:59:25 pmSame with the 40G drive in an old laptop I use as a desktop spare machine at work. I run it as a media player, and use it to check internal network only so I can simply use the web interfaces of printers to save walking there to check the "It has a red light and won't print my job WAAAH and I can't be bothered to read the FSCKING display on the front to see what the error is", so I can take a cartridge where needed, or put paper in the machine. Yes there are people who think that they work by making paper and toner out of thin air, and complain they can't print when the power is out.

author: amyk
author_rank: Super Contributor
timestamp: August 02, 2015, 01:55:23 pm
content: Quote from: Psi on August 02, 2015, 12:59:25 pmIt's been running on average for over 200h between each spinup/spindown. That contributes to longevity, as start/stop cycles cause the most wear.I also follow a "zero tolerance" policy on reallocated sectors - if any new ones develop after the drive has been in use, I replace the drive since more are coming.

author: BradC
author_rank: Super Contributor
timestamp: August 02, 2015, 02:00:19 pm
content: Quote from: george graves on August 01, 2015, 10:39:09 amFinally a topic I can contribute to. Back in about 2003 as Mr Gibson was finalising SR6 I spent a long time running it in an instrumented VM to actually watch its interaction with the ATA controller.Let's get a couple of things straight. Spinrite has not performed magic for about 20 years. It does not and can't "disable SMART" and it does not interact or interface with the drives firmware (or any other bullshit people say it does). What it does do (and I'm mystified about why nobody else is doing this) is invoke "dynastat" recovery.This does work for one specific failure. You have a PC that dies (GPF, bluescreen, hang, whatever) when it hits a bad sector on the disk. Spinrite reads the disk end to end and when it hits the dud it invokes "Dynastat". This reads the dud sector using the ATA read_long (and sometimes some other low level commands to the same effect) repetitively. This command returns the raw sector contents in whatever form they come off the disk having failed ECC recovery. If in the process the disk gets a good read, the disk itself will re-write that sector. Problem solved. In most cases it won't, so Spinrite builds a simple statistical model of each bit in the sector. It does this X times (where X can be defined on the command line) and at the end of X times it writes the statistical model back to the sector on the disk. In general this writes a "best guess" of the sector contents back and in most cases it solves the problem.On a failing disk, Spinrite will just run it into the ground and trash it completely, but for mum's PC which is just failing to boot it's a quick fix that makes the problem go away.So it does work, for certain use cases based on old technology and smaller capacity drives. It is useless for "preventative maintenance" or other mystic magic Steves followers promote it for, but hey people buy snake oil and put it in their cars, or monster cable. At least this *does* do something for specific cases.

author: max666
author_rank: Frequent Contributor
timestamp: August 02, 2015, 03:53:17 pm
content: Quote from: madires on August 01, 2015, 08:53:54 pmNot only that, but drives in a server (or any multi-bay enclosure) also have to endure higher vibrations from all the closely mounted neighbouring drives, which are happily humming and clicking away.However I myself don't follow that advice, because I'm too cheap. But I also had surprisingly little issues with my countless desktop drives running in RAID5 24x7.

author: wraper
author_rank: Unknown
timestamp: August 02, 2015, 07:22:04 pm
content: Found on Russian forum that in HDDs of these series a seal under connector becomes leaky.How to bring a second life to it

author: Dave Turner
author_rank: Frequent Contributor
timestamp: August 02, 2015, 08:10:49 pm
content: I was part of the team running a small/medium sized company's network from '98 to '09. The network and server farm expanded considerably during this period. The one thing we tried to do was mix batches of disks for the raids, mirrors and SAN racks. I don't recall the source of the information that caused me to do this, however we never lost information due to the relatively few failed server drives we suffered.If you think about it, it makes 'gut' sense to mix drive sources provided they have identical properties, and whilst I can't work the probability statistics out I'm sure there are those that can.There is a reason for not being on the 'bleeding edge' just as there is for not using a 'dot zero' product when one's business depends on very high reliability.Dave

author: edavid
author_rank: Super Contributor
timestamp: August 02, 2015, 08:51:55 pm
content: Quote from: madires on August 01, 2015, 08:53:54 pmIs there any evidence that server/RAID drives have lower failure rates?

author: sync
author_rank: Frequent Contributor
timestamp: August 02, 2015, 09:29:33 pm
content: Quote from: edavid on August 02, 2015, 08:51:55 pmDoes over 15 years experience count?

author: edavid
author_rank: Super Contributor
timestamp: August 02, 2015, 09:48:47 pm
content: Quote from: sync on August 02, 2015, 09:29:33 pmNo, I don't think anecdotal evidence has any value when it comes to disk drives. It has to be actual statistics.

author: sync
author_rank: Frequent Contributor
timestamp: August 02, 2015, 09:59:47 pm
content: Quote from: edavid on August 02, 2015, 09:48:47 pmSorry, I didn't done any statistics. I only have experience with hundreds of server drives and about 100 desktop drives in servers or RAID systems. And the differences are dramatic.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 02, 2015, 10:43:34 pm
content: Quote from: senso on August 02, 2015, 12:42:06 pmWell I think when I get around to it I'll attempt a head swap VERY CAREFULLY and when it's all closed up again I'll do a PCB swap too. So the bad drive will get new heads and its corresponding PCB.Without knowing exactly what is on the EEPROM (is it head data? is it platter data? is it BOTH ? ) then I don't know if this will even be successful for me. But I'm willing to try. I'm rebuilding my server with new drives first, and I'll attempt to repair and clone the bad drives later.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 02, 2015, 10:54:01 pm
content: Quote from: sync on August 02, 2015, 12:31:16 pmYes I know, an LTO-3 drive is about $200 and tapes cassettes are cheap ($15) , so I can easily get several tape drives and do weekly and monthly backups without overwriting them.I would prefer LTO-5 or 6, but to do the same with LTO-5, 6 is going to cost upwards of several thousand dollars.Hmm.. I just took a look online at some retail stores, I can get a 4TB WD external USB 3 drive on sale right now for $149. At that price, it trumps everything. I can get 2 for $300 and backup till the cows come home. Gonna do it. I think these are the ones with the embedded USB 3 interface on the drive electronics, it's not a SATA internal with a USB3 bridge card. So it's cheap.

author: edavid
author_rank: Super Contributor
timestamp: August 02, 2015, 10:59:26 pm
content: Quote from: codeboy2k on August 02, 2015, 10:43:34 pmDo the PCB swap first... much lower risk of killing the drive.

author: edavid
author_rank: Super Contributor
timestamp: August 02, 2015, 11:01:28 pm
content: Quote from: codeboy2k on August 02, 2015, 10:54:01 pmIt's only 2.5" external drives that have integrated USB controllers.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 02, 2015, 11:02:25 pm
content: Quote from: amyk on August 02, 2015, 01:55:23 pmJuding by your and other comments I think I should also have zero tolerance to reallocated sectors from now on. Seems like I might have saved my data if I already had followed that practice. My tolerance level has always been higher, assuming that disk technology is difficult, and remapping of sectors is a way to get around these difficulties, but it doesn't mean my data is lost. Even SSDs do this today, too.From here out, I'll take a zero tolerance to any growing remapped sectors.I also read online that some people put new drives through a grueling 2 or 3 day read/write stress test and check the SMART data before and after. If there is any re-allocated sectors or read/write failures during the tests, they RMA the drives. Maybe I should do that too.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 02, 2015, 11:05:26 pm
content: Quote from: edavid on August 02, 2015, 10:59:26 pmOK. If that doesn't work then I'll try to bring over the head stack.There's also some serial port commands that I'd really like to know what they are and what I can do. I might just be able to bring the old drive back to life without swapping anything.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 02, 2015, 11:17:22 pm
content: Quote from: edavid on August 02, 2015, 11:01:28 pmIt is the WD Elements 4TB. I think it might be 3.5". This is the one I mean:From the USA (with free shipping to Canada)$109 USD + no TAXhttp://www.bhphotovideo.com/c/product/1077555-REG/wd_wdbwlg0040hbk_nesn_4tb_elements_external_hd.htmlIn Canada (in my city, actually!) (also free shipping )$149 CAD + TAXhttp://www.ncix.com/detail/wd-elements-4tb-desktop-external-bb-103285-1145.htm

author: madires
author_rank: Super Contributor
timestamp: August 03, 2015, 10:47:06 am
content: Quote from: edavid on August 02, 2015, 08:51:55 pmIf you are looking for statistics, a quick web search will provide you with data. And I suggest to read some datasheets for desktop and server/RAID harddisks. It's not just about failure rates. The slow error recovery process of a desktop disk causes delays/timeouts in a RAID system, for example.

author: madires
author_rank: Super Contributor
timestamp: August 03, 2015, 11:07:54 am
content: Quote from: sync on August 02, 2015, 09:59:47 pmI fully concur. The differences are also quite visible in low performance, i.e. SOHO, applications. Desktop disks are designed to be cheap and to last a lot of start/stop cycles, not to run 24x7.

author: wraper
author_rank: Unknown
timestamp: August 03, 2015, 11:24:57 am
content: Quote from: madires on August 03, 2015, 11:07:54 amA lot of Enterprise/Consumer models have identical hardware, the only difference seem to be in firmware. So with such models there will be a performance difference because the firmware is optimized for different tasks, but being more reliable is very doubtful. Seagate 7200.11 and ES.2 had exactly the same reliability (crap hardware) issues and even shared most of the firmware bugs (one of them caused HDD to lock if bad sectors appear).

author: sync
author_rank: Frequent Contributor
timestamp: August 03, 2015, 11:42:37 am
content: Quote from: madires on August 03, 2015, 11:07:54 amYes. Seagate rates it's desktop disks for 2400h/year (~6.6h/day). So running them 24/7 is outside of their specification. It's like running an electronic component above it's ratings.That's is one problem I have with the backblaze.com statistics. They should only shown disk which are rated for 24/7.

author: madires
author_rank: Super Contributor
timestamp: August 03, 2015, 02:02:01 pm
content: Quote from: wraper on August 03, 2015, 11:24:57 amI found following in the datasheets:7200.11: MTBF 750,000h, high-performing, eco-friendly desktop storageES.2: MTBF 1,500,000h, business-critical Tier 2 enterprise drives, designed for 24x7 operation

author: wraper
author_rank: Unknown
timestamp: August 03, 2015, 03:03:28 pm
content: Quote from: madires on August 03, 2015, 02:02:01 pmAnd shows nothing more than marketing, of course Enterprise drives will have better MTBF (on paper).Yet MTBF is quiet meaningless figure as it doesn't show life expectancy at all, just percentage of devices expected to die in a predefined time period.Nonetheless both of those series were plagued like hell, and that MTBF was completely off unless they tested that MTBF for like less than a week.BTW:http://knowledge.seagate.com/articles/en_US/FAQ/174791en?language=en_USQuote

author: edavid
author_rank: Super Contributor
timestamp: August 03, 2015, 03:27:58 pm
content: Quote from: madires on August 03, 2015, 10:47:06 amThe only data I found indicates that desktop drives are more reliable:https://www.backblaze.com/blog/enterprise-drive-reliability/QuoteThat's more of a bug intentionally introduced into desktop drives. Of course it's not relevant to non-RAID systems.

author: sync
author_rank: Frequent Contributor
timestamp: August 03, 2015, 04:10:52 pm
content: Quote from: edavid on August 03, 2015, 03:27:58 pmFrom the first link of the article (https://www.backblaze.com/blog/how-long-do-disk-drives-last/).Interesting graphs. In my experience the failure rate of enterprise drives after 5 years is <10%. The 2nd graphs shows that Backblaze already had higher failure rates after 3 years with their consumer drives. And not all of them are desktop drives. They also using better ones and they selecting the better models.Furthermore these graphs agree with my opinion to replace consumer drives after two years in 24/7 operation as precaution.

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 03, 2015, 10:04:16 pm
content: Just another way of drawing the famous "Bathtub Curve":The 'bathtub curve' hazard function (blue, upper solid line) is a combination of a decreasing hazard of early failure (red dotted line) and an increasing hazard of wear-out failure (yellow dotted line), plus some constant hazard of random failure (green, lower solid line).

author: edavid
author_rank: Super Contributor
timestamp: August 03, 2015, 10:32:37 pm
content: Quote from: sync on August 03, 2015, 04:10:52 pmThey addressed that:Quote

author: helius
author_rank: Super Contributor
timestamp: August 04, 2015, 02:27:00 am
content: Theargumentum ad ignorantiamshould be easy to spot.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 10, 2015, 07:22:46 am
content: So to get my RAID server back up I decided to just go with 2 x 3TB disks in a simple mirror.I bought the WD Red 3TB drive, WDC WD30EFRX-68EUZN0, and a Toshiba 3TB DT01ACA300After 72 hours of continuous write/read/compare patterns of 0x55,0xAA,0xF0, 0x0F, 0x00 it was all fine on both drives. Smart data showed 0 for the important metrics, and on both drives. So I feel safe to use these drives.Code:196 Reallocated_Event_Count 0x0032 100 100 000 Old_age Always - 0197 Current_Pending_Sector 0x0022 100 100 000 Old_age Always - 0198 Offline_Uncorrectable 0x0008 100 100 000 Old_age Offline - 0However, the WD drive had UDMA_CRC_Error_Count = 36 , while the Toshiba drive had this value at 0 still.Should I suspect a cable problem? I'm currently swapping the cable and re-running the tests to see if the CRC errors go up on the other drive now, but the tests takes 9 hours to complete 1 pattern. However, with 36 CRC errors in 72 hours I expect to see 1 new error every 30 minutesSo it could be a cable, or a drive, or a controller problem.. If it moves with the cable I'll know. If it stays with the drive it could be a controller or a drive problem, so I'll switch controllers then to rule that out.

author: knks
author_rank: Regular Contributor
timestamp: August 24, 2015, 05:26:23 am
content: I remember reading somewhere - putting the HDD to fridge/freezer may make it readable

author: helius
author_rank: Super Contributor
timestamp: August 24, 2015, 09:42:16 am
content: Likely an urban legend from the days when stiction was a common problem. A drive with stiction can't turn its spindle motor because the heads are cold welded onto the surface. If the bond forces between the head and platter are broken, the drive will at least spin up and may work. Freezing worked on the principle that the heads and platters would thermally contract along different directions. Another technique was tapping the drive with a hammer while switching on power.Stiction stopped being an issue when head assemblies were redesigned to prevent it. Freezing is unlikely to help now, and could cause condensation which quickly corrodes the data surface.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 24, 2015, 03:58:28 pm
content: Freezing doesn't work with new drives.. I'm not even going to try it.I'll do a head swap when I get time to make a portable "clean-box" .As for that last post of mine, where I saidUDMA_CRC_Error_Count = 36on one of the new drives, I swapped cables, swapped controller ports, but nothing new happened and nothing changed after days of additional read/write testing. That number stayed at UDMA_CRC_Error_Count = 36 and the other drive never gained any errors when it was swapped around too.So I think that was an anomalous event that caused the controller attached to that specific drive to briefly screw up, but I'm not seeing it again.Today, both drives are in service now, and it's still UDMA_CRC_Error_Count = 36 for that drive and 0 for the other drive.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 24, 2015, 10:08:55 pm
content: Joining this party very late, but had to comment. Codeboy you say that this is just personal data "not worth recovering". I would encourage you to think long and hard about this before you do anything that reduces your chance of recovering the data. The type of data you describe represents many, many hours of your involvement. Capturing, digitizing, interviewing, whatever. When you say it isn't worth recovering you are placing zero value on that time, and also zero value on any future time you may spend attempting to re-create portions of the lost data.I am speaking from personal experience, having lost a huge chunk of personal data to a moment of stupidity. I went ahead and spent some serious dollars on recovery, and while there were still many things lost, I have never regretted the money spent. I have rued the inadequate backup strategy, the inadequate planning that resulted in the data loss and other things, but not the investment in recovering the data. In my case the investment (after converting dollars to hours) was less than ten percent of the hours originally spent getting the data onto the hard drives.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 25, 2015, 01:00:54 am
content: (I'm wordy) TLDNR: I agree with what you're saying and I know I need to keep the limits of my abilities in check.Hi thanks! yes your comments hit home with me, it certainly is worthwhile data and does not have $0 actual value, but I'm trying to decide if it has $1600 value ? That's the cost since it is part of a raid, and the few sites that I probed wanted $800 per disk in the raid so they can recover files at the file level. I am not sure if that means the total is $1600 or $2400 yet (2/3 drives or 3/3 drives)I don't want that kind of recovery, and if I can find a reputable data recovery company that is willing to just mirror the data off the disk onto a new disk (with block read errors set to 00000), then I will have 2 disks of the raid again, and then I can setup a degraded raid and recover my own files. The blocks that could not be read will have checksum errors during my recovery and will be skipped by ZFS, it's good about that, so I may ultimately lose just a few files. Much better scenario indeed. It sounds even plausible, as this failure mode appears to be well known and common for the drive I had.I've taken disks apart before (ones that were broken already!) so I'm familiar with the internals, but I have never tried to make a bad one work again in this manner. I have some old disks here on the shelf, so I am planning to build a "clean-box" and test out a head swap on some working disks. Some people online did this already and had mixed results. Good thing is I don't smoke or drink and have ultra-stable hands. If I can get the heads off both disks without incident, and put one back, and don't let the heads touch or snap or bend or all the other bad things that can go wrong, then I might have a chance. But I will certainly practice on about 10 other disks I have here already.I plan on screwing down the donor drive and the bad drive to the tabletop so they don't move during the process, and screw the jig to the tabletop. Even a bump on the table top during the surgery will kill it, so I am still worried about that possibility and want to be aware of it. The operating room needs to be rock solidI've certainly been thinking about how to save the data. At this stage I just have the disks set aside, no freezer, no serial port attempts. I've duplicated the good drive onto another drive, so I have two copies of the one good drive. I'll be making another block-by-block copy onto the new server (since it's empty now !) and then I'll still have two good copies when and if I decide to tear into the good drive for it's heads.If I'm unsuccessful with the practice runs then I won't even bother, and I'll wait until I have the spare cash and take it somewhere that can recover it block by block.Cheers, and thanks for your comments. It certainly does make me think twice about what I believe I am capable of and what I am actually going to be capable of.

author: BradC
author_rank: Super Contributor
timestamp: August 25, 2015, 01:25:28 am
content: Quote from: knks on August 24, 2015, 05:26:23 amDespite what the others are saying, freezing *can* work in a specific instance. Freezing works where the failure in the drive is related to mechanical tolerance of either the spindle bearing, or more usually the head actuator bearing.In that case, I wrap the drive in several freezer bags, and using long power cables and a USB/ATA(or SATA) adapter) put the whole thing in the freezer and run the recovery in one hit. The more thermal cycles the worse it works.Like I said, it's a single scenario, it's rather un-common compared to other failures, but in the right case with the right failure it can help immensely.

author: wraper
author_rank: Unknown
timestamp: August 25, 2015, 01:29:47 am
content: Quote from: helius on August 24, 2015, 09:42:16 amStill very actual problem for notebook HDDs, personally disassembled such with stuck heads. Though almost non existent for 3.5" HDDs.

author: kc8apf
author_rank: Regular Contributor
timestamp: August 25, 2015, 03:41:41 am
content: Quote from: codeboy2k on August 24, 2015, 03:58:28 pmThis is a pretty common problem at my work. We collect extensive data on every hard drive at installation, during usage, and at failure. UDMA CRC errors tend to show up at installation and correlate very strongly with being resolved simply by reseating the cable. It's not necessarily a bad cable or connector but just that it didn't quite seat well.

author: Delta
author_rank: Super Contributor
timestamp: August 25, 2015, 07:20:03 am
content: Excuse my lack of knowledge, but why do you need more than one good disk to recover your data? I thought the whole point of a RAID array was that there was redundancy between disks?

author: helius
author_rank: Super Contributor
timestamp: August 25, 2015, 08:46:04 am
content: As was addressed earlier in the thread, multiple drive failures sometimes happen in clusters. Identical drives from the same batch, run for the same number of hours, have a higher probability of failing at the same time; especially if the failure is caused by a firmware bug.

author: wraper
author_rank: Unknown
timestamp: August 25, 2015, 09:35:12 am
content: Quote from: Delta on August 25, 2015, 07:20:03 amBecause he had RAID5 with 3 hard drives, not RAID1.Quote

author: codeboy2k
author_rank: Super Contributor
timestamp: August 25, 2015, 12:27:21 pm
content: Quote from: helius on August 25, 2015, 08:46:04 amand I learned my lesson about using 3 identical drives from the same batch in a RAID. My rebuilt server has just 2 new drives in a RAID1 and these are from Hitachi and Western Digital. I made sure to buy two different drives this time.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 25, 2015, 12:37:19 pm
content: Quote from: kc8apf on August 25, 2015, 03:41:41 amThanks! I'll just keep an eye on it now.What kind of extensive data do you keep for drives? If I had huge numbers of drives in play I'd probably keep a database for each serial number with smart data snapshots so you can plot it over time, and additional data such as performance data too, i.e. monthly read/write speed tests . If I was monitoring drives for pre-failure that would be helpful.. Something I think I should have done at home here too, and maybe I will now.

author: kc8apf
author_rank: Regular Contributor
timestamp: August 25, 2015, 03:18:49 pm
content: Pretty good guess. At install time, they run the drive through a set of diagnostics that does things such as read/write every sector, verify read and write performance at the inner and outer diameters, etc. They then record a snapshot of SMART as well as a bunch of vendor-provided statistics. While in use, SMART and the vendor-provided statistics are recorded every 15m. Filesystem reported errors (read/write failures mostly) are recorded if they happen. Any information the SATA controller can provide is logged too. If those correlate with any patterns we've previously seen for failing drives, the OS is told to stop using the drive. We then run a more extensive version of the diags that we ran during install. If it all checks out, which is often the case, the drive gets put back into use. If anything fails, the drive is erased and RMA'd.The failure patterns are derived by running regular analysis over the entire set of data for every drive ever deployed. At this point, that data set is more information about drive behavior than the drive manufacturers have. They don't have the budget or need to keep that many drives running constantly. They usually only keep a few 1000 drives of the most recent models running to see when they start to fail and why.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: August 25, 2015, 06:37:20 pm
content: I am glad you are at least thinking about the value of your data. Personal time is very hard to assign a dollar value to. Those who try to value it the same as their pay scale are making one of two errors, both of which are huge, and are in opposite directions. One error is assuming that they can convert every hour they have into dollars. Even those who work hourly consulting jobs have trouble making this true as there are always down times or expenditure limits, and most others cannot even come close. The other error is that time with their wife, kids, mates and hobbies has no value, or is valued only at their pay rate. That time can in fact be priceless.I am guessing that you didn't have these drives full, perhaps only two thirds of a terabyte of data. Probably a sizeable fraction of that is totally disposable (Utube videos, tunes you never listen to and so on). But there is likely to be several hundred gigabytes of things you would rather not lose (tunes you DO listen to, web data that has been useful, instruction manuals and so on) and things you would really hate to lose (scans of family photos, downconversions off of video tapes, your own notes and creations, .mp3s from recording sessions or off of old vinyl, clever bits of code and the like). The things you would rather not lose can be fairly easily replicated, but it takes time measured tens of hours. The really hate to lose stuff is even slower to get back, and in many cases impossible.Even if the budget doesn't have room for the expense right now you might be better off in the long run putting these disks on a shelf until you can save the money.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 26, 2015, 12:31:59 am
content: I'm definitely one who cringes every time I hear someone say their off-time (or personal time) is worth as much as their billable time. I simply know that's not true. I usually have arguments with my wife about this ALL THE TIME! because she thinks my personal time is worth my billable time, so if I spend a week in a woodshop building furniture because I enjoy it, than in her eye I am losing money because I'm not being productive. She would want me to buy the furniture and use my time to make money. We argue this a lot, much to my chagrin. But I agree with you, that it's wrong for me to say it has zero value.As to the contents of the disk, you nailed it, it is exactly all that you said. From my second post in this thread :QuoteSo I certainly hope to get it back, but if I can't then I'll be able to recreate most of it too.

author: Chris C
author_rank: Frequent Contributor
timestamp: August 26, 2015, 04:25:31 am
content: Quote from: helius on August 24, 2015, 09:42:16 amIt's not an urban legend. I've recovered two "click death" drives by chilling them, one PATA, one SATA. Both 3.5", and both continued to operate only as long as they were cold. Multiple cycles of chilling and recovery were necessary. With high priority files first just in case, but I was able to achieve 100% recovery on both.As for why it works, I don't know. But limiting the possibilities to stiction, or even to something mechanical, seems myopic. It could be that there's a cracked solder joint, IC wire bond, or some other intermittent that could be pushed temporarily back into good contact by thermal contraction. Or because something electronic has gone out of spec, and electronics work better with less noise when cold, allowing it to edge just enough back into spec to function.

author: madires
author_rank: Super Contributor
timestamp: August 26, 2015, 12:14:07 pm
content: When you search youtube for "Scott Moulton" you'll find several of his Defcon presentations about harddisk recovery.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 26, 2015, 04:42:22 pm
content: I was able to recover an old QUANTUM hard drive (anyone remember them?) back in the 90's via freezing, so it does work, with some drives.I was told repeatedly and read over and over again in many forums that freezing modern high density TB level drives just does not work, and may cause more damage making it completely unrecoverable.So I really don't even want to try it.Besides, I don't think it's the kind of problem that freezing may fix. There is no stiction, the drive spins, trys to read a few things on the platters, the heads move, click 2 or 3 times , retract then the motor spins down.Quote from: madires on August 26, 2015, 12:14:07 pmThanks, I'll do that!

author: Chris C
author_rank: Frequent Contributor
timestamp: August 26, 2015, 11:28:54 pm
content: Quote from: codeboy2k on August 26, 2015, 04:42:22 pmBoth drives I recovered did the exact same thing. Spin up, seek and click, seek and click, seek and click, then shut down. The second was a Seagate 1.5TB, SATA2.Funny how the world is full of consumer products with bad lead-free solder joints that open up when they reach a certain temperature, sometimes room temperature. And technicians who identify a failed IC by hitting it with freeze spray, bringing it back to life. Yet when it comes to chilling a hard drive, people always say it's only good for certain mechanical issues like stiction, or it's an urban myth. Hard drives contain electronics and solder, do they not?Though I can imagine how condensation on the platters, especially if it freezes, could cause damage. I doubt the internals of my drive ever got down to actual freezing point, as I only had it in the freezer for 30 minutes at a time. I wish now I'd taken some temperature measurements. But it was enough for 10-15 minutes of reliable operation. Took many cycles and pretty much all day. Putting an ice pack on the drive while operating didn't noticeably help (I tried). Oddly, on the very last recovery cycle, the drive seemed to start working for good. Ran it for an hour straight without issue, during which time I double checked my recovery.I see you live in Canada, though I don't know exactly where. Average temp and relative humidity right now for Ontario is 68°F and 64%, putting your dew point at 54°F. Chill the drive to just short of that (or whatever your actual conditions are), and you will have no issues with condensation.Swapping platters is a pretty extreme idea, so here's another one. You might be able to partially dessicate the drive, allowing you lower temperatures still. Will it be sitting around for some days/weeks, while you decide what to do? Put it in a sealed container with silica gel or calcium chloride. Dessication could be accelerated by pumping air out of the enclosure to some pressure the drive can tolerate, wait for a few hours, backfill with dry nitrogen, wait again, repeat a few times.Or is it possible your drive is hermetically sealed? I've heard mention of some new ones being sealed, and filled with helium.Yep, I remember the Quantums. Especially the aptly named "Fireball".EDIT: I seem to remember something about condensation tending not to form distinct droplets on very clean surfaces. I can't think of anything cleaner than a hard drive platter, so maybe short-term, condensation isn't so big an issue as one might imagine. Even if decent-sized droplets did form, wouldn't they be flung off the platters by centripetal force, before they achieve the required velocity to cause collision damage to the head? Just musing at this point.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 27, 2015, 01:34:30 am
content: yes, the drives will be sitting around for a while..I have a vacuum food bag sealer and dessicant.. maybe I can throw in a dessicant pouch and vacuum seal the harddrive and let it dry out.yes, I think the biggest worry is condensation when you bring it out of the freezer .. so definitely need to keep it above the dewpoint.I need 4 hours of operation to image the entire disk.. that would still be my goal.. just make an image.From what's been said here, I understand that platter swaps are difficult because of alignment issues, and that a head swap is more likely to be successful, so that's the route I would take if I get there. I'll not move the platters out of alignment.

author: kc8apf
author_rank: Regular Contributor
timestamp: August 27, 2015, 03:01:02 am
content: For 2TB and up, the primary failure more is head failure due to physical damage. Impurities on the platters stick up like mountains and the head fly height varies enough that the head occasionally runs into the peaks. I've got electron microscope shots of this somewhere from a pile of drives that my team asked the vendor to do a full teardown and analysis on.Head or media failure lines up exactly with the described symptoms (spin up, heads released, a few seeks, park heads, spin down). It could be a few of the firmware sectors went bad though it would need to be across the redundant copies. Head failure causes the self tests to fail.For modern Seagate drives, if the firmware gets damaged, the drive will go to a boot loader mode that reports a special model and serial number.

author: max666
author_rank: Frequent Contributor
timestamp: August 27, 2015, 03:08:53 am
content: Quote from: Chris C on August 26, 2015, 11:28:54 pmI still don't think a broken solder joint is very high on the list of most likely drive failure causes.Man I wish I hadn't used my Quantum Fireball for lethal magnetic field strength testing. The Fireball I have, had been in daily office use for many many years, without any issues (easily 10 years).But I wanted to know if I could quick erase a HDD by swiping it with a magnet (D70mm x H40mm N42). Long story short, nothing magnetically I tried resulted in any bad sectors.So I opened her up and let her spin, and to my surprise the thing worked perfectly fine without the lid, admittedly this wasn't a very high density drive (I believe 30 GB or so).Now you won't believe me, but I even touched the spinning surface very lightly with the screwdriver and even that didn't produce any bad sectors. I had to push the screwdriver hard enough to scratch to surface in order to get bad sectors. (Disclaimer: the excessive scratiching seen in the picture is just me going to town, it didn't take that much scratching to produce the first bad sectors)

author: kc8apf
author_rank: Regular Contributor
timestamp: August 27, 2015, 03:13:37 am
content: Quote from: max666 on August 27, 2015, 03:08:53 amThe platters are composed of many layers. The outermost layers are a lubricant and then a protective coating. The actual magnetic layer comes next.

author: codeboy2k
author_rank: Super Contributor
timestamp: August 27, 2015, 04:40:11 am
content: Quote from: kc8apf on August 27, 2015, 03:01:02 amAnd that's why I want to try a head swap in a "clean box". But if the media is damaged and it can't load the firmware, the bootloader mode should still allow it to load firmware from the serial port, correct? I would need to have the properly formatted firmware and the correct software download tools (which I don't have!). I think I need to get a serial port up and see what it says ..

author: knks
author_rank: Regular Contributor
timestamp: August 31, 2015, 11:17:49 pm
content: Another urban legend I heard - how to easily create a "clean room" for safe HDD opening. Go to your bathroom, turn on hot water in your shower until the bathroom is full of steam, turn off the water and wait for steam to condensate (on the walls, not the HDD). All the dust will be removed by steam.Is it myth or not?

author: helius
author_rank: Super Contributor
timestamp: September 01, 2015, 12:03:58 am
content: This bathroom technique is used by photography hobbyists. It does reduce airborne dust, but the dust will still be present on the walls and counters so is not a "clean room" in any sense. Dust also sheds from your skin and clothes.

author: codeboy2k
author_rank: Super Contributor
timestamp: September 01, 2015, 08:01:25 pm
content: Interesting technique, but I don't think I'll try it at homeI'm still planning to make a simple clean box using two identical plastic tubs from IKEA or some other store, and duct tape them together, a large one on the bottom for the work space, one smaller one (cut down in height) on the top for the filtration and laminar flow box. I'll put a HEPA filter feeding into the bottom box, and a smaller 5 micron filter feeding into the top box. A blower fan will be in the top box, sucking air from outside through the top 5-micron filter and pushing it into the bottom box through the HEPA filter. So the bottom box will have positive pressure and the top box will have negative pressure.I'll cut an opening into the bottom box for my hands, and positive clean air will exit via this opening, keeping dust out. I'll use clean room gloves (I requested a sample from a distributor) and I'll use some non-linting cloth to cover my arms. I am considering using this conical 1 micron PE filter bag from Amazon as arm covers:1 Micron Singed Polyester FilterI'll cut a hole in the small end of that conical filter for my hands to exit, and wear the gloves over top. Basically making arm covers that can block 1 micron particles. This should keep skin cells and small dust particles on my body out of the clean box work area and anything that did get in would get (hopefully) blown out the front via the positive pressure.The whole setup might be less than $100.00 and I'll do my best to make sure I have a proper clean environment to work in.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: September 01, 2015, 10:10:50 pm
content: You might want to find some information on clean room startup. I am no expert, and don't see anything fundamentally wrong with your approach, but do know that if there is any chance of mechanical jarring to your boxes and or any surfaces inside them (like the outside of the disk drives) those surfaces need to be clean or they will shed particles. Full size clean rooms spend a lot of time cleaning surfaces at startup as part of the solution to this problem.Your solutions might include things like letting your box run for hours after loosening, but before removing screws and things like that.

author: codeboy2k
author_rank: Super Contributor
timestamp: September 02, 2015, 07:01:24 pm
content: Thanks CatalinaWOW (Catalina Island? I had a great time there!)Those are great tips. Someone commented previously to wipe down the surfaces so I'll be doing that.Ah..here it is:Quote from: pickle9000 on August 01, 2015, 03:40:10 amPickle9000's suggestion to wipe everything down is in line with what you are saying... that getting a clean startup is a necessity. I was planning on doing this and also just running the box for 24 hours before going in. I also read about removing the PCB outside the clean room, and wiping down all the external surfaces of the hard disk drive before bringing it inside. Your idea to loosen the screws and let it run a bit before opening it is a good idea too.Also, jarring the table or the box is on my list of things to avoid. Plastic tubs are very lightweight, perhaps I'll use some angle brackets and duct tape to hold it to the table top surface. I also plan on building a clamp on the table top to clamp down both drives so they don't move during surgery. I'll use the mounting screws and angle brackets. Finally, a little hand-held puffer is handy for blowing things off, and I have that already.I'll read up more on clean room startup, that's a good search term I did not know about.