8.0-RELEASE: disk IO temporarily hangs up (ZFS or ATA related problem)

[Alexander Zagrebin]

> > The disks are used for mirrored ZFS pool.
> > I have noticed that the system periodically locks up on 
> disk operations.
> > After approx. 10 min of very slow disk i/o (several KB/s) 
> the speed of disk
> > operations restores to normal.
> > gstat has shown that the problem is in ad6.
> 
> Want you try this patch and report?:
> http://people.freebsd.org/~attilio/lockmgr_lostwake.diff
> 
> It should apply to STABLE_8 and if not, just report and I will help.

Thanks fo your attempt to help!
I've successfully applied this patch to RELENG_8_0, recompiled
kernel and required modules (krpc, opensolaris,zfs),
but nothing has changed. The problem still exist.

-- 
Alexander Zagrebin