Topic
1 reply Latest Post - ‏2013-01-29T11:14:32Z by k0da
k0da
k0da
3 Posts
ACCEPTED ANSWER

Pinned topic SAS array performance problem on VIOS

‏2013-01-28T09:26:53Z |
Hi,

I have external disc enclosure EXP 12s connected to PCI Express x8 Ext Dual-x4 3Gb SAS Adapter. I've created RAID10 disk on top of 6 SAS disks.

Weird thing is that performance is really slow.
dd if=/dev/zero of=/dev/hdisk1 bs=1M count=100
gives me 1.6MB/sec
hdisk1 xfer: %tm_act bps tps bread bwrtn
100.0 1.6M 384.0 0.0 1.6M
read: rps avgserv minserv maxserv timeouts fails
0.0 0.0 0.0 0.0 0 0
write: wps avgserv minserv maxserv timeouts fails
384.0 29.2 2.3 42.2 0 0
queue: avgtime mintime maxtime avgwqsz avgsqsz sqfull
0.0 0.0 0.0 0.0 11.0 0.0

If I dd to rhdisk then I'm getting 43MB/sec.

timex dd if=/dev/zero of=/dev/hdisk1 bs=1M count=100
100+0 records in.
100+0 records out.

real 67.40
user 0.00
sys 0.12

timex dd if=/dev/zero of=/dev/rhdisk1 bs=1M count=100
100+0 records in.
100+0 records out.

real 1.50
user 0.00
sys 0.03

Is that expected?
Updated on 2013-01-29T11:14:32Z at 2013-01-29T11:14:32Z by k0da
  • k0da
    k0da
    3 Posts
    ACCEPTED ANSWER

    Re: SAS array performance problem on VIOS

    ‏2013-01-29T11:14:32Z  in response to k0da
    Attached adapter to the Linux LPAR and got 130MB/s.

    So there must be a tunable in VIOS (AIX)