RE: OT: cluster size=0

[Rich Payne <rdp talisman alphalinux org>]

On Sat, 24 Mar 2001, Eugene Chu wrote:

> Speaking of file system problems, I have one that maybe folks on this
> list can help solve.
> 
> I recently got a API UP2000 with two 833 MHz processors and 3 disk
> drives.  A 36 GB drive is used as the boot disk running some recent
> dist of RH linux.  Two 73 GB drives were RAID 0'd together to form a
> very large volume for data storage.  All drives are on the base SCSI
> bus on the mother board, which I think is Ultra-II Fast Wide SCSI.
> (This was the way it was delivered, and I haven't had a chance to do
> much with it yet.)  If anyone from API is watching, this is the system
> you provided to WSM for me to evaluate.

Yes, the onboard is Ultra 2, 80MB/sec.
 
> I tried to run a simple file I/O test program to check the performance
> of RAID 0 on the same bus, as I've heard of some people getting pretty
> good results this way.  The program is very simple; it simply creates a
> file, and starts to write a specified buffer size of random data to the
> file a specified number of times.  In the standard tests that I run,
> the buffer size is 1 MB, mem aligned to 65536 bytes, and I write 1024
> of them to create a 1GB file.  My test brought lots of SCSI errors in
> the system log file, and the mounted partition became inaccessible.  I
> was able to dismount it, but remount attempts gave errors complaining
> of unsupported fs type.  fsck got similar errors.

Can you get us the SCSI errors? Also, can we assume that you've got the
correct cabling and proper termination?

> I tried running the same test on the 36 GB root disk, and managed to
> complete the run, but only got about 3.3 MB/s transfer rate.  This
> seems awefully slow for Ultra-II SCSI.  According to the specs I've
> seen for most 36 GB disks, they should be able to run between 20-45
> MB/s rates depending on which zone your data happens to have landed,
> with average of 30 MB/s.
> 
> Right now, the system is down for some reason, and I can't get to it
> until Monday.  In the mean time, can anyone provide any pointers on
> disk and RAID setup in Linux?  I am most interested in high
> performance, but also need reliability (who doesn't?).

Can you tell us what's installed on it, and which kernel version? I've run
across problems with the adaptecs and kernels before about 2.2.17 or 18,
can't remember the actual driver revision, though I can look it up.

--rdp

> thanks in advance,
> eyc
> 
> 
> 
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-- 
Rich Payne
rpayne@alphalinux.org			www.alphalinux.org