Read / write timeouts on SATA disks connected to ICH9

[Miroslav Lachman]

Pieter de Boer wrote:
> Hi there,
>
>> what kind of disk I/O is going on. If actual I/O is very little, then
>> something weird is going on with regards to the number of interrupts
>> being seen on IRQ 23. mav@ might have some ideas, otherwise I'd
>> recommend rebooting the machine and seeing if the number drops. If so,
>> it may be that the OS has some sort of bug where a disk timing out or
>> falling off the bus causes interrupt problems. (It's too bad you don't
>> have AHCI on this system. It handles stuff like this much more
>> elegantly...)
> Well, due to a UFS snapshot panic the box was rebooted, and now I only
> see around 1500 interrupts per second, while syncing the mirror.

I seen high interrupts on 7.x systems after pulling out/in one drive in 
gmirror [1] even if it was successfully disconnected by gmirror remove + 
atacontrol detach and reconnected by atacontrol attach + gmirror insert.
It was not 100% reproducible, but it seems the bug is still there in 8.x.

[1] 
http://lists.freebsd.org/pipermail/freebsd-stable/2008-October/046003.html

Miroslav Lachman