Machine stops for some seconds with ZFS

[Tommi Lätti]

> I'm not sure about these are being the same. When I see these "stops",
> nothing happens. gstat shows no IO, and everything goes very quiet for some
> painful (10s of) seconds. Also, buildworld doesn't do too heavy IO, at least
> for these drives.

Well that's what I experienced. iostat says 0, machine is kind of
responsive, unless you try to read or write from the zfs pool..

> BTW, we are doing tests in a completely different environment with ZFS and
> NFS (15k drives, with BBWC), and it seems something similar happens there
> too, resulting in a freeze in the end.
>>
>> Combine with 5400 rpm consumer drives... well...
>>
>
> Doesn't really count, but these drives are 7k2.

If it's a zfs arc problem it would definitely manifest on 15k drives
too, what I meant that the impact might be unnoticeable. But since I
don't have a nice SAN to test with right now I can't try it out with
100+ disks.

-- 
br,
Tommi