From: young@mdavcr.mda.ca (Shawn Young)
Newsgroups: comp.sys.sgi.misc
Subject: Re: Disk striping performance
Date: 25 Jan 93 21:35:34 GMT

olson@anchor.esd.sgi.com (Dave Olson) writes:
: In <3980@mutt.mdavcr.mda.ca> young@mdavcr.mda.ca (Shawn Young) writes:
: | I was wondering if anyone had any I/O benchmark results for striped disk sets on
: | SGI boxes, either for just the striped disks, or relative to single disk
: | partitions. I'm looking for something that'll give me an idea of maximum and 
: | expected real-world throughput, and a relative measure of increase/decrease in
: | performance with respect to individual disks.
: 
: Yes, we have them, but there are way too many variables to give you
: an answer with the info you have provided.  The numbers depend a
: great deal on machine type, and raw vs filesystem, controllers used,
: usage patterns, etc. etc.
: 

Well, the final configuration we are looking at uses hardware which is (I find)
covered by a non-disclosure agreement, so I am not really in a position to 
elaborate very much. I was hoping for a generalized technical note or something 
of that order. Benchmark data using a multiprocessor R4000 box with single disk 
and striped partitions, where disk I/O is the application bottleneck, would be 
helpful for now (additional examples weouldn't hurt, either :-) ). I am trying 
to ballpark some performance figures and choose or evaluate metrics for a 
performance study on a proposed configuration. Final numbers will be based on 
the actual hardware, but are not necessary for this part of the task. 

We are looking at a multiprocessor box (4 CPUs), with a 1.6GB system disk and
two striped partitions of 8GB and 6.4GB, respectively, comprised of 1.6 GB
disks. These "product" partitions will contain highly transient data, consisting
of very large data files which will be transferrred to another host/media soon
after they are completed and then removed from the disk, as new data files
are generated.

These files can get very large, and may in some cases fill a whole partition
(e.g. all 8GB of the larger), in which case, they may be broken at a convenient 
place and completed on the other large product partition.

Third party disks and controllers are not an issue. Standard SGI-provided
disks and SCSI (at present, anyway) controllers are expected to be used.

If any further info. is required by the SGI guys, we can take this offline in 
e-mail, or I can fill in the blanks after the target hardware is officially 
announced.

Thanks again,

Shawn

--
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Shawn Young          | MacDonald Dettwiler    | "The wages of sin may well be
Phone:  604-278-3411 | 13800 Commerce Parkway |  death; but after taxes, it's 
Fax:    604-278-2936 | Richmond, B.C., Canada |  probably just a really tired
Email:  young@mda.ca | V6V 2J3                |  feeling." - A comedienne who's
        !uunet!van-bc!mdavcr!young            |  name I cannot recall
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* 	The opinions stated herein are not necessarily those of my employer or 
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