Suggestions needed, throughput prob on Areca R6

Hi. I have a file server with a raid array and I'm having some lousy
performance numbers. This is what I'm working with:

Opteron 2.2ghz CPU on Asus M2N-LR mobo
4GB RAM
Areca ARC-1160ML2 controller
16 Western Digital WD10EACS drives with TLER disabled
One RAID volume set:
14000GB
RAID6
64KB stripe size
Write back cache mode
Tagged command queuing enabled

I installed PerformanceTest 7 and ran the disk test against the array.
Configured it for Standard Win32 API (uncached), 50/50% read/write, 100%
sequential, 4095 MB file size, 8192 byte block size. When the test was done
it reported 24.42 MB/s. I ran it again with the same setup but Standard
Win32 API (cached) and it only went up to 27.24 MB/s.

I ran it a third time with 100% reading, no writing uncached and got 145.6
MB/s, then the same cached and got 170.49 MB/s.

Any ideas what I could do to increase performance? Thanks!

Ken wrote:
Hi. I have a file server with a raid array and I'm having some lousy
performance numbers. This is what I'm working with:

Opteron 2.2ghz CPU on Asus M2N-LR mobo
4GB RAM
Areca ARC-1160ML2 controller
16 Western Digital WD10EACS drives with TLER disabled
One RAID volume set:
14000GB
RAID6
64KB stripe size
Write back cache mode
Tagged command queuing enabled

I installed PerformanceTest 7 and ran the disk test against the array.
Configured it for Standard Win32 API (uncached), 50/50% read/write, 100%
sequential, 4095 MB file size, 8192 byte block size. When the test was done
it reported 24.42 MB/s. I ran it again with the same setup but Standard
Win32 API (cached) and it only went up to 27.24 MB/s.

I ran it a third time with 100% reading, no writing uncached and got 145.6
MB/s, then the same cached and got 170.49 MB/s.

Any ideas what I could do to increase performance? Thanks!

The mixed numbers look normal to me. A mix of small reads and writes
(8k in your case) will allways cause a massive prformance hit.

Your linear read performance is not to good, I suspect you are
dealing with a bus-limit here. Is this controller in a 64bit/133MHz
PCI-X slot and is that speed enabled in the sysmem BIOS?
May also be an internal limit of the controller or of the benchmark tool.

A possible additional problem is the small stripe size. Maybe increase
that to 256kB and see what happens?

Arno