ZFSKnownProblems - needs revision?

[Ben Kelly]

On Apr 8, 2009, at 5:59 PM, Miroslav Lachman wrote:
> Rsync is used for "snapshots" with --link-dest= (each day has own  
> directory and all unchenged files are hardlinked to previous day and  
> I have history of two month back).
> Backups are stored on /vol0 with compression enabled. (compression  
> is enabled on /usr/ports, /usr/src, /var/db/pkg, /vol0)
>
> # df -hi /vol0/
> Filesystem    Size    Used   Avail Capacity  iused    ifree %iused  
> Mounted on
> tank/vol0     2.7T    1.3T    1.3T    50% 17939375 11172232   62%   / 
> vol0
>
> This backup server is in service from october 2008 with just one  
> panic (kmem related). After proper loader.conf tuning it is working  
> well.

You might want to look at this commit if you are using rsync --link- 
dest and getting kmem panics:

   http://svn.freebsd.org/viewvc/base?view=revision&revision=187460

and the MFC:

   http://svn.freebsd.org/viewvc/base?view=revision&revision=190837

It seems quite possible to me that kmem panics could be mistakenly  
attributed to zfs when the name cache is eating up memory.

Hope that helps.

- Ben