2498 Ultra3 and 2104 RAID5 configure performance very very bad ???

From: L (leed@CHELE.CAIS.NET)
Date: Mon Jul 22 2002 - 15:46:35 EDT


we have IBM P660 and AIX 4.3.3 O.S. on it. The P660 have 2498 Ultra SCSI3
RAID adapter card and connect seperate cables to 2104 disk array. We
configure 6 disks hardware RAID5 through "PDAM". while I load data from
LTO tape driver (high speed tape driver 15~30MB/sec) to this RAID5. the
performance is very very slow. Load 2Gb data toke 2hours to finish. I
use "topas" to check and found this RAID5 wrte speed is "550KByte/sec". I
called IBM support and support engineer told me nothing he can help.

Does anyone have expereince on it and can give me suggestion?

The configuration on 2498 RAID5 are:

   6 disks raid 5
   stripe size: 16K
   command Queue Depth: 16

Thanks.



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