Re: ZFS patches.

Pawel Jakub Dawidek wrote:
> Hi.
> 
> 	http://people.freebsd.org/~pjd/patches/zfs_20080727.patch.bz2
>... 
> Please test, test, test. If I get enough positive feedback, I may be
> able to squeeze it into 7.1-RELEASE, but this might be hard.
> 
> If you have any questions, please use mailing lists
> (freebsd-fs_at_FreeBSD.org would be the best).
> 
> Thank you in advance!
> 

Hello,

I have updated a test machine with the patch. Before the patch, the 
machine was fairly stable using vm.kmem_size=1024M and 
vfs.zfs.arc_max=200M. After the patch, I ran a few test with the 
following loader.conf:

vm.kmem_size="512M"
vm.kmem_size_max="512M"
zfs_load="YES"
vfs.zfs.arc_max="100M"
kern.maxvnodes="400000"

I am now getting back "kmem_map too small" panics within a few minutes 
of cvs update of ports. If I have a look at kstat.zfs.misc.arcstats.size 
in the mean time, I see the following:

kstat.zfs.misc.arcstats.size: 275762656
kstat.zfs.misc.arcstats.size: 279666312
kstat.zfs.misc.arcstats.size: 284994776
kstat.zfs.misc.arcstats.size: 298142184
kstat.zfs.misc.arcstats.size: 304219168
kstat.zfs.misc.arcstats.size: 312289376
kstat.zfs.misc.arcstats.size: 318243832
kstat.zfs.misc.arcstats.size: 331942168
kstat.zfs.misc.arcstats.size: 335262560
kstat.zfs.misc.arcstats.size: 344793136
kstat.zfs.misc.arcstats.size: 359504168
kstat.zfs.misc.arcstats.size: 334877376
kstat.zfs.misc.arcstats.size: 334877376
kstat.zfs.misc.arcstats.size: 334877376
kstat.zfs.misc.arcstats.size: 334877376
kstat.zfs.misc.arcstats.size: 334877376
((panic here))

(2 seconds between reads)

It seems that arc_max is ignored or arc_reclaim is not working as expected.

Tanks for your work, Pawel.