Tape drive - Page 1
Forum section: electronics / general

author: olkipukki
author_rank: Frequent Contributor
timestamp: October 04, 2020, 12:07:38 pm
content: I'm looking for off-premises archive and backup solution that can be shipped and stored in a long-term without issues.The cloud is not option here, although AWS keep hot-backups, I don't want a strong dependency on Glacier or similar Azure Archive stuff etc.After taking into account current requirements and further grow, LTO-6 generation fits into storage capacitance.Never dealt with tapes, so no clue what is all about.Is anyone using the **subj**?What are major/minor disadvantages?Does drive/tape depend on a manufacture (such as RAID controllers)?

author: S. Petrukhin
author_rank: Super Contributor
timestamp: October 04, 2020, 05:57:57 pm
content: Tapes have a lot of of disadvantages, including mechanical aging, sequential access, instability to temperature and aggressive environment, they can simply break. However, due to redundant code, they can provide good guarantees. Information is written to the tape as a video signal, in slanted strips. I think this is no longer relevant, it seems impossible to find equipment (streamers) and cassettes produced now. Apparently, it is now more accessible and in all respects more convenient to create separated RAID arrays.

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: October 04, 2020, 10:31:26 pm
content: LTO isn't helically scanned. The 'L' stands for "linear" ... the technology comes from DEC's DLT. Helical scanning gives excellent density but would be too slow ... modern LTO drives write at hundreds of MiB/s.I have installed and configured LTO tape libraries for several clients. Unless you need the very specific benefits of tapes (mostly the ability to have many tapes sitting on the shelf for a long time), I would not recommend them as a solution for your off-site storage. Bear in mind that tape drives are expensive, and support contracts on them are much more expensive than on e.g. a server, because they wear out. (Magnetic) hard drives in caddies or even USB 3 enclosures will be cheaper and far easier for you to set up.

author: Cerebus
author_rank: Super Contributor
timestamp: October 05, 2020, 12:14:30 am
content: "Never underestimate the bandwidth of a van load of tapes."Tape is awkward, even if you have an automated tape library to handle it. Whatever the downsides, it makes it trivial to move a complete copy of your backups to another place that is unlikely to burn, flood or explode at the same time as your primary site.Insert obligatory warning that the most fantastic backup system is worthless until you have tested it, and ensured that you can do a complete, practical, successful restore from it.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: October 05, 2020, 10:56:43 am
content: We use tape *a lot*, not just for our datacenter backup using large tape libraries but also in the form of individual tape drives. In the past we used a range of formats (Exabyte 8mm, AIT, DDS, DLT) but in the last decade they have all been replaced by LTO.Tape has a number of advantages over other backup media like optical discs or hard drives:- The cartidges are very robust and survive abuse other media wouldn't- The cartridges contain only the media and some simple mechanics while the whole read/write mechanism with its complex and sensitive mechanics stays in the tape drive - which adds to the robustness of cartridges- For archiving, tape is a much better medium than hard drives or optical disks, and if stored correctly will survive for decades- Unlike hard drives, LTO tapes cartridges can be repaired in a non-clean room environment and with basic tools (BTDT a few times)- Because tape is no direct-access medium (i.e. it has no file system that is visible to the OS and other programs) and is written to in streams, it's not susceptible to malware (however, the archived data itself can of course still contain malware if the system was affected). The caveat here is LTFS, a direct access filesystem for LTO-5 and later, which can turn a tape into a pseudo direct-access device.- Media costs are generally low (the drives are expensive, though)We ship LTO cartridges all around the globe and not always are they handled appropriately, but they always survive. We occasionally get one with a stucked reel lock after it has been dropped but that's easily fixable.The tape drives themselves are also very reliable, at least what the standalone drives are concerned (tape libraries are a different topic and there's a reason they are covered under support contracts). Right now all LTO drives are I believe made by only two manufacturers: Quantum (which also makes drives labelled as HPE and Tandberg) and IBM (which are also labelled as Dell). In general, the Quantum drives are less reliable than the IBM drives, but the difference isn't exactly earth shattering and Quantum drives by itself are still very reliable. Just keep them in a clean environment and use the cleaning cartridges as required (not less often and not more often than the tape drive indicates).Just make sure your system can actually deliver the sustained rates the tape drive expects, as otherwise you'll get a lot of start/stopp repositioning which unnecessarily strains the mechanics. Most newer LTO drives support throtteling where the drive reduces it's performance if the host can't keep up but there's a limit to that.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: October 05, 2020, 11:06:42 am
content: Quote from: S. Petrukhin on October 04, 2020, 05:57:57 pmMost computer tape drives made don't use helical scan but simple linear recording. Pretty much all of the helical scan formats (DDS, AIT, Exabyte 8mm) have been dead for a number of years, mostly because their reliability track record was a lot worse than for linear formats.QuoteWell, which is understandable as the term "streamers" generally refers to the QIC40/80-based floppy streamers, tape drives using the small QIC format cartridge which were connected to a PC's FDD controller. Theyw ere quite common back in the early '90s but suffered from a number of issues which were specific to those drives. It shouldn't be surprising that these drives are no longer available.QuoteNo, it's not!RAID IS *NOT* A BACKUP!RAID is a method to maintain availability of a disk subsystem in case of disk failure. This is all there is. It is *NOT* a form of backup!

author: Doctorandus_P
author_rank: Super Contributor
timestamp: October 06, 2020, 03:00:21 pm
content: As a simple hobbyist I just use regular HDD's as backup media, and put them in simple commercially available silicone sleeves. I don't go throwing these things around and never had an issue with them.If I was more serious, I'd make some kind of padded suitcase (or two) and put a full HDD with it's silicone condom in an ESD bag with some dessicant and seal it hermetically with such a kitchen bag sealer, and add a 3rd layer to prevent the water & moisture barrier from getting small punctures from grains of sand and such.For a long, long time HDD heads are parked with the heads lifted from the disk and are quite robust, but they do have a limit on G-forces.Price of HDD storage is also similar to tapes, but you don't need an extra tape drive.As backups are all about redundancy, have you considered using both?Relying on a single backup is completely bonkers with today's storage prices. If a HDD with any of my backups fails, I open it for the magnets, bend the disk (or cut first surface mirrors out of them) and grab another HDD with data.For me, I also used old left over HDD's. For a more serious Backup I would not. Best is probably to use a HDD for a few months, to weed out early fails, and after that only use it for backup to reduce bearing wear.A friend of mine one had a HDD that failed to start (this was in the '90ies), and I helped him by holding it in my hand and rotating it back and forth so the inertia of the disks gave it an exta jollt to overcome the increased friction. Then of course we proceeded to backup that drive and it was the last time it was used. These day's you monitor the SMART data.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: October 07, 2020, 08:53:03 am
content: Quote from: Doctorandus_P on October 06, 2020, 03:00:21 pmYes, and these can be exceeded by a simple drop. On some drives the robustness even depends on which side the drop is.Hard Drives are certainly a good option for hobbyist use but they can't compete with the robustness and reliability of LTO cartridges.QuoteThat really depends on the amount of data you want to offload.For example, I can buy new LTO-5 (1.5TB/3TB) cartridges for approx $30, and that gives me approx 2.2TB of usable capacity. A LTO-7 (6TB/9TB) cartridge is $80, and with the data we have I get over 8TB on one. An LTO-8 (12TB/30TB cartridge) I can get for approx $100, and that gives me more than 25TB on storage.While I can get new 2TB drives for $50, I haven't seen any 8TB drive for anywhere near $80.Of course the tape drive itself is pretty expensive (around $2k for an LTO-7 drive and around $3k for an LTO-8 drive) but the more data there is to store the cheaper the tape becomes over HDD.Then there's the transfer rate. Even fast SATA hard drives max out at around 200MB/s, and sustained the rate drops even further (often below 100MB/s). SMR drives (which are spreading at the lower cost end of the HDD market) can drop even further (<30MB/s). In comparison, LTO-5 streams at 280MB/s sustained, and LTO-7/8 can go up to over 700MB/s sustained (which is more than what the fastest SATA SSDs can achieve as peak rate!).QuoteI agree, a proper backup strategy is important independent of the medium.QuoteWell, hard drives do still fail sporadically, or sometimes even without SMART warnings. At least bearing issues are mostly gone thanks to the move to FDBs some 15 years ago (although they can potentially dry out if stored for a long period of time).

author: BravoV
author_rank: Super Contributor
timestamp: October 07, 2020, 09:05:46 am
content: Tape needs to be stored in dry place or even better climate controlled, as it can easily infected by mold.

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: October 07, 2020, 09:23:48 am
content: Quote from: BravoV on October 07, 2020, 09:05:46 amYes, older types of tape were susceptible to fungus growth because of the binder used (even floppies are affected). But modern magnetic tape uses different binders that makes them a lot more resistant to the effects of humidity.And hard drives are susceptible to humidity, too, less so in the formation of mold but in the corrosion of parts (including components on the PCB).LTO cartridges survive just fine if stored in a simple cabinet away from excessive heat or sunlight. An aircon isn't needed unless the place is in a desert or in the rain forest.

author: olkipukki
author_rank: Frequent Contributor
timestamp: October 13, 2020, 08:00:12 am
content: Thanks for your input.I already using cold-backups as a copy of whole systems (that mentionedhere),and keep copy-all data on NAS and some remotely.I'm after long term off-premises backup, digital content keeps growing and a risk lose a lot of these keep growing too.Ideally, if I can adopt same method for decade(s) and stay with a conservative approach after that.Quote from: Wuerstchenhund on October 07, 2020, 08:53:03 am$2K for new LTO-7? Where I can buy it?

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: October 13, 2020, 01:21:50 pm
content: Quote from: olkipukki on October 13, 2020, 08:00:12 amSounds like a planQuote from: Wuerstchenhund on October 07, 2020, 08:53:03 am$2K for new LTO-7? Where I can buy it?Sorry, this is from our suppliers, but it's unlikely they sell outside the large enterprise space.If you don't have a business account with one of the larger vendors and you buy retail then you should be able to find a LTO-7 for around $2.7k (HPE StorEver LTO-7 internal, should go up to around $3k for an external one) - if you're in the US, that is.