FreeBSD 9.2-RELEASE stability?

[Mark Felder]

On Mon, Sep 30, 2013, at 14:01, Brett Glass wrote:
> How stable are folks finding FreeBSD 9.2-RELEASE to be? The 
> improvements are welcome, but there have been a few troubling 
> messages about kernel panics and VM issues on the various mailing 
> lists. It's never clear until the release drops whether these are 
> actual problems with the software or hardware defects in individual 
> systems, so I am eager to hear how the new release is working for
> everyone.
> 

I upgraded our two main backup servers which are doing I/O via
rsync/rsnapshot and sending ZFS snapshots to the other remote site every
15 minutes.

I had several instances where the machines went unresponsive. They
didn't panic, and they did respond to CTRL+ALT+DEL on the console, but
they lost all networking and wouldn't do anything else. The only change
was I enabled zfs prefetch which I previously had disabled for
performance reasons. It never caused this issue on 9.1 when I had it
enabled, though. The fix definitely was turning off prefetch again which
doesn't bother me too much, but I can't use this environment to try to
help debug it as it's important production data.