I have an IBM x346 with five 320gig drives (FastSCSI) and two volumes defined on top of this RAID (c: and e:) When I put nbench on this (in response to complaints of slow disk access) I see that the write speed is 15mbs versus 60mbs on a server with a cheap SATA RAID 5. The read speed on the IBM is actually superior. Any ideas or performance tips for improving the write speed on this RAID 5, or ideas why it may be so dismal? I used the single large RAID 5 because we needed the disk space. These are high-end disks, I would have thought that they would outperform generic SATA-based RAIDs on other servers. The machine itself is 64-bit Windows Server 2003 Ent with 8gigs ram, and not under general stress.
I know it's kind of a longshot: just looking for ideas how to diagnose, solve such an issue. There are no errors being logged by the RAID software and apparently all the disks are fine.