ZFS trouble: unbelievably large files created

[David Samms]

On 10/15/10 15:09, Oliver Fromme wrote:
>   >  ls -kls shawxp/var/amavis/.spamBAD
>   >  total 13352131
>   >        771 -rw-------  1 110  110           684032 Oct 15 12:02
>   >  auto-whitelist
>   >          1 -rw-------  1 110  110               40 Oct 15 12:37 bayes.lock
>   >       1284 -rw-------  1 110  110          1294336 Oct 15 12:38 bayes_seen
>   >       4229 -rw-------  1 110  110          4227072 Oct 15 12:38 bayes_toks
>   >    5025103 -rw-------  1 110  110     553184002048 Oct 15 12:38
>   >  bayes_toks.expire3515
>   >    8320745 -rw-------  1 110  110  140743122878464 Oct 15 12:14
>   >  bayes_toks.expire97254
>
> Ok, so those files are so-called "sparse" files, i.e. they
> contain holes that don't actually occupy disk space.
>
> The numbers in the first column indicate the amount of
> physical disk space allocated (in KB).  That's about 5 GB
> for the first file and 8 GB for the second (this is also
> consistent with the "total" value in the first line of the
> ls output, i.e. about 13 GB).
>
> That's still quite big, but certainly not in the TB range.
> I do not know why amavis creates such large sparse files,
> though.

Under UFS I don't observe amavis creating the sparse files.  The problem 
is fairly repeatable, not on demand, but occurs several times a day. 
High disk activity is a sure sign amavis is creating large files.  Task 
shuts down normaly and cpu load is low.

This is a production server but I have moved all critical customer jails 
back to UFS so can do testing if anyone has any ideas of what to look for.