Many processes stuck in zfs

[Frédéric Bour]

Le Tue, 9 Mar 2010 10:15:53 +0100,
Stefan Bethke <stb at lassitu.de> a écrit :

> Over the past couple of months, I've more or less regularly observed
> machines having more and more processes stuck in the zfs wchan.  The
> processes never recover from that, and trying to reboot only gets the
> entire system stuck, without any console messages.  I can enter the
> debugger, and I have saved a couple of dumps.
> 
> The situation seems to be triggered by zfs receive'ing snapshots from
> the sister machine (both synchronize their active ZFS filesystems to
> each other, using zfs send and zfs receive).  It appears it's the
> receiving causing trouble.
> 
> Both machines run 8-stable from mid-February, with a single-disk ZFS
> pool, with ARC limited to 512M, prefetch and ZIL disabled via
> loader.conf.
> 
> What should I be looking at to further diagnose?
> 
> 
> Thanks,
> Stefan
> 

Hi,

I encounter almost the same problem with a 8-STABLE build
from the same time. When working a lot on files inside ~/,
the directory get locked, any command trying to access it (from "ls" to
application reading their configuration files) get stuck.

The system is an amd64 desktop computer, 4GiB of memory and
vfs.zfs.prefetch_disable is set to 0.