[SO]HO Software RAID5 server: which implementation should I choice?

[Steven Schlansker]

Miroslav Lachman wrote:
>
> Do you have any stability issues after tuning? What settings you are 
> using?
> I am testing ZFS for a short time with these values:
> vm.kmem_size="1024M"
> vm.kmem_size_max="1024M"
> vfs.zfs.prefetch_disable="1"
> kern.maxvnodes="400000"
> vfs.zfs.zil_disable="1"
>
> (on Sun Fire X2100 with 4GB of RAM and FreeBSD 7.0-RELEASE amd64)
>
> It seems to be stable.
>
> Miroslav Lachman
> _________________________

I'm also running ZFS and wanted to share my experiences.  It doesn't 
cope well with low-memory environments, but I've successfully run with 
2GB ram and 3TB disk with no problems on both i386 and amd64.  amd64 
needs a little bit of tuning - increasing kmem and whatnot (well 
documented, not very difficult/stressful)
i386 needs a bit more tuning and a kernel recompile (increase KVA_PAGES) 
but once you get it working it runs fine.

I've heard dire warnings that disabling the zil is a terribly bad idea 
if you're running anything that tries to ensure data file consistency 
(like a database and nfs or something)


To sum up - tune it and it will work wonders for you.  Don't try to run 
it with minimal RAM though - I've had good luck with 2GB+ (and half or 
more of that allocated to kernel memory)