Incredibly slow A1000 (in RAID0 mode)

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Article #174

#174

From: Mikhail Teterin
Date: Fri, 22 Jul 2005 18:20

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Hello!

We are planning to slowly retire our A1000 devices, and disks from one of
them are already being used to replace failing disks in the others.

In the mean time, I wanted to use this partially dismembered array for
storing some easily recoverable data temporarily.

So instead of the redundancy of RAID5, we configured it for the roomier
RAID0. Out of 12 slots, there are currently 7 disks in it (Fujitsu 36Gb).

Trouble is, the array is very slow... The highest throughput is just over
4Mb/sec (read or write), which is, probably, less than a single disk can
do. From a 7-disk array unburdened by the RAID5 complexity I expected, _at
least_, 20Mb/sec.

We uploaded the latest firmware and applied the OS patches (Solaris 9). No
noticable difference :-( The healtchek reports "Optimal". Changing the
interleave (segment) size from 128Kb to 256Kb did not seem to affect much.

Any suggestions? Thanks a lot!

        -mi

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From: Mikhail Teterin <usenet@aldan.algebra.com>
Newsgroups: bln.comp.sun,comp.sys.sun.admin,comp.sys.sun.hardware,comp.sys.sun.misc,comp.unix.solaris
Subject: Incredibly slow A1000 (in RAID0 mode)
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Date: Fri, 22 Jul 2005 14:20:01 -0400
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