Questions about ZFS Tuning

[Volodymyr Kostyrko]

17.09.2012 13:36, Jamie Paul Griffin wrote:
> When I installed FreeBSD on my Lenovo Think Center Desktop I created a full ZFS Root file system using Matthew Seaman's excellent article:
>
> 	http://www.infracaninophile.co.uk/articles/install-on-zfs/
>
> My system now is: /home/jamie $ uname -a
> FreeBSD kontrol.kode5.net 9.1-PRERELEASE FreeBSD 9.1-PRERELEASE #4 r240560: Sun Sep 16 18:40:56 BST 2012     root at kontrol.kode5.net:/usr/src/sys/amd64/compile/KONTROL  amd64
>
> I've been wondering about ZFS tuning and have read some articles, including the FreeBSD handbook and wiki articles and also some posts in the FreeBSD forum.
>
> The FreeBSD handbook [http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/filesystems-zfs.html], section 21.2.1.3 Loader Tunables
> suggests adding tunables to /boot/loader.conf for ALL architectures - which I tested:

Handbook is old and cripsy about that all thing yet provides a useful 
link to http://wiki.freebsd.org/ZFSTuningGuide

  - you don't need kmem_size/arc tuning on amd64 generally;
  - zfs.zfs.prefetch_disable=0 will cause system eat more RAM then 
without it;
  - there are a lot of tunables but you should learn what you are doing 
before setting anything, for example changing recordsize for already 
running MySQL database filesystem will do nothing at all.

-- 
Sphinx of black quartz judge my vow.