From: Jonathan Williams (jonathw@shubertorg.com)
Date: Tue Oct 15 2002 - 17:24:07 EDT
Ok...restore problem solved!! Thanks go to Cory Erickson for suggesting I look
into the writeback_cache on the HSZ70 controller. Sure enough, it was set to
"nowriteback_cache". Once I changed it, the disks INSTANTLY jumped up to
5000KB/sec (which may be slow still, but at least it's on par with the
production machines).
Big thanks go to Charles Ballowe as well for suggesting I use "collect" to
monitor the restores in the first place. What a wonderful program!!
Thanks to everyone else who responded as well.
Jonathan Williams
Unix Systems Administrator
The Shubert Organization, Inc.
---Original Message---
> Tru64 5.1, patch 3, Alpha ES40 machines.
>
> I have a test machine here, and the only difference between it and our
> production machines is that the production machines are on a SAN with HSG80
> controllers, and the test machine is not on a SAN and has it's own HSZ70 disk
> cabinet.
>
> I'm trying to track down an informix restore slowness we've been noticing on
> this test machine. I've been using 'collect' to capture data during various
> restore and backup operations. I've come to the conclusion that it is
> definitely a disk issue, and only with writing to the disks. When comparing
> this test machine to a real production machine, all the numbers are pretty
> close, except for a restore operation that writes to disks out on an HSZ70
> controller. On the HSZ70, it seems to max out writing to disk at about 2500
> KB/sec, while on our other systems that use an HSG80 write at about 5000
KB/sec
> (which would explain why the restores take twice as long on this system).
> Reading from the HSZ70 disks is much like the production machines at around
5000
> KB/sec.
>
> So I'm wondering, is this normal behaviour for an HSZ70? To write to it's
disks
> at around 2500 KB/sec...or is there a problem? I'm hoping that it's just a
> difference between the two types of controllers. I've been looking at some of
> the manuals, but can't find anything that seems too helpful.
>
> Oh, and both the HSZ70 and the HSG80 use the same type of disks (DS-RZ1FC-VW
> 36.4GB).
>
> TIA
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