Re: ZFS patches.

Pawel Jakub Dawidek writes:
 > Hi.
 > 
 > 	http://people.freebsd.org/~pjd/patches/zfs_20080727.patch.bz2
 > 
 > The patch above contains the most recent ZFS version that could be found
 > in OpenSolaris as of today. Apart for large amount of new functionality,
 > I belive there are many stability (and also performance) improvements
 > compared to the version from the base system.
 > 
 > Check out OpenSolaris website to find out the differences between base
 > system version and patch version.
 > 
 > 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.
 > [...]

Thanks Pawel!

I have a version of -CURRENT from 7-29-08 running on an AMD 3800+ with
2GB of RAM and two Seagate ST3300622AS disks.

This machine was previously running zfs filesystems using -STABLE.
It uses a root on zfs configuration based on

  http://yds.coolrat.org/zfsboot.shtml 

I tested for stablilty by firing up a bunch of xterms on my desktop
workstation, ssh'ing into the system and running a bunch of stuff in
parallel.  The list of stuff settled down to be: two while(1) loops
that did "dd if=/dev/random of=FILENAME bs=1M count=1000" (w/ distinct
filenames) then removed the file; rsyncing a large directory of mp3's
from another local machine; make -j 4 buildworld; and several windows
with top, systat -vmstat 1, etc....

With the -STABLE zfs I ended up with the following settings to achieve
stability:

 vm.kmem_size="512M"
 vm.kmem_size_max="512M"
 vfs.zfs.arc_max="192M"

I started off with no tuning, added the kmem_size{,_max} settings,
then added the arc_max setting and tuned it down until it didn't
wedge.

With the experimental code on -CURRENT I needed the following
settings:

 vm.kmem_size="512M"
 vm.kmem_size_max="512M"
 vfs.zfs.arc_max="128M"

I don't know if I just got lucky with the larger arc_max under -STABLE
or if something's changed.

Otherwise the new code seems to be behaving nicely.

g.