Sun Fire V250 disk performance

[jmiturbe]

Hello,

We have a Sun Fire V250 server, with 2x1280MHz CPUs, 2GB RAM and 6x72GB Hard Disks.

We configured a RAID1 (2xHD) and a RAID5 (4xHD) using Solaris Volume Manager. As we started to test the volumes, we noticed a very poor performance, specially on the RAID 5. I know that it's usual with software raids, but without no server load I expected a bit more from a Ultra160 SCSI controller and 73.4GB - 10000 RPM Ultra-320 disks (part number XRA-SC1CB-73G10K).

For example, it took about 2min to create a 650MB file on the raid5:

# time mkfile 650m testraid5

real 1:51.6
user 0.0
sys 9.7

Only 5,5MB per second?????

The mirror was a bit faster:

# time mkfile 650m testraid5

real 13.6
user 0.0
sys 3.6

Anyway, only 37,79MB per second for a mirror.

Is it normal?

Looking at iostat (iostat -x 3 30) when creating a 650MB file on the raid 5 we get measures similar to:
device r/s w/s kr/s kw/s wait actv svc_t %w %b
md75 0.0 42.7 0.0 5333.4 0.0 6.7 156.0 0 100
....
sd1 84.7 307.7 1128.0 4551.9 0.0 5.6 14.2 0 99
sd2 111.0 359.3 1114.7 4524.6 0.0 7.2 15.3 0 100
....
sd8 83.7 306.0 1117.4 4529.9 0.0 5.5 14.1 0 99
sd9 56.3 252.3 677.3 3652.6 0.0 3.8 12.5 0 94

On the mirror:

device r/s w/s kr/s kw/s wait actv svc_t %w %b
md50 0.3 438.7 2.7 54754.2 0.0 84.3 192.0 3 100
md51 0.3 438.7 2.7 54754.2 0.0 80.5 183.3 0 100
md52 0.0 438.7 0.0 54754.2 0.0 79.7 181.6 0 99
....
sd0 0.3 440.3 2.7 54765.4 0.0 81.4 184.8 1 100
....
sd7 0.0 440.3 0.0 54765.4 0.0 80.2 182.1 0 99

Shouldn't I expect a greater performance on both raids, and specially on the raid5 a much greater bandwidth?

Any ideas? Suggestions? Can you tell me how to investigate this problem?

Thanks in advance,

jmiturbe

 

[bfitzmai]

jmiturbe. I have almost the identical V250. I only run mirrors on the server but, I am getting the same performance with the mirrors as you are.