Terrible disk performance with LSI / FreeBSD 9.2-RC1
Frank Leonhardt
frank2 at fjl.co.uk
Wed Aug 7 22:08:26 UTC 2013
On 07/08/2013 21:36, J David wrote:
> It feels like some sort of issue with the
> bus/controller/kernel/driver/ZFS that is affecting all the drives
> equally.
>
> Also, even ls takes forever (10-30 seconds for "ls -lh /") but when it
> eventually does finish, "time ls -lh /" reports:
>
> 0.02 real 0.00 user 0.00 sys
>
> Really not sure what to make of that. An attempt to do "ps axlww |
> fgrep ls" while the ls was running failed, because the ps hangs just
> as long as the ls. So it's like the system is just repeatedly putting
> anything that touches the disks on hold, even if all the data being
> requested is clearly in cache. (Even apparently loading the binary
> for /bin/ls or doing "ls -lh /" twice in a row.)
As a suggestion, what happens if you read from the drives directly? Boot
in single user and try reading a Gb or two using /bin/dd. It might
eliminate or confirm a problem with ZFS.
Regards, Frank.
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