Terrible disk performance with LSI / FreeBSD 9.2-RC1

[Terje Elde]

On 8. aug. 2013, at 00:08, Frank Leonhardt <frank2 at fjl.co.uk> wrote:
> 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.

If not too inconvenient, it'd be very interesting to see what'd happen if you were to physically disconnect (data and power) 5 of the 6 drives, then boot and dd from the remaining disk to /dev/null. Then repeat with another drive. 

You could boot from USB to leave the system itself otherwise untouched. 

The reason I'm suggesting is that I'm wondering if this can be down to a power or cable-issue, locking things up or causing retransmits, etc. 

Not sure if this would always be logged, others might be able to enlighten that issue. 

Terje