zfs, 1 gig of RAM and periodic weekly

Freddie Cash fjwcash at gmail.com
Mon Feb 27 22:48:06 UTC 2012

On Mon, Feb 27, 2012 at 11:02 AM, Nenhum_de_Nos
<matheus at eternamente.info> wrote:
> On Mon, February 27, 2012 15:33, Chuck Swiger wrote:
>> On Feb 26, 2012, at 9:07 PM, Eugene M. Zheganin wrote:
>> [ ... ]
>>> all with zfs and one gig of RAM.
>> This isn't a sensible combination; I wouldn't try to run ZFS on anything less than 4GB...
> regardless of the pool size ?
> I was planning on making an atom board a file server for my home, and I have two options: soekris
> net6501 2GB RAM and intel board powered by the 330 atom (says 2GB limited as well). My plans are
> to use from 4 up to 8 disks, and they should be 2TB at least.
> As its for home use, some p2p software and mostly music listening and sometimes movie streaming.
> should 2GB be that bad, that I should drop it and use UFS instead ?
> I may run any version of FreeBSD on it, was planning on 9-STABLE or 9.1.

You can get away with 2 GB of RAM, if you spend a lot of time manually
tuning things to prevent kmem exhaustion and prevent ZFS ARC from
starving the rest of the system (especially on the network side of

Definitely go with a 64-bit install.  Even with less than 4 GB of RAM,
you'll benefit from the large kmem size and better auto-tuning.

Do not, under any circumstances, enable dedupe on a system with less
than 16 GB of RAM.  :)

If at all possible, find a motherboard that will let you use more RAM.
 2 GB is usable.  But 4 GB is the sweet spot for a simple file server.
 And 16 GB is best for a system with over 10 TB of storage in the

My home media server is a 32-bit install of FreeBSD 8-STABLE (Dec 2011
vintage) with only 2 GB of RAM, using 4x 500 GB SATA drives in 2
mirror vdevs (boot off USB stick).  Every couple of weeks it'll lock
up, usually under heavy torrent load.  Prior to doing a bunch of "tune
loader.conf; reboot; crash; repeat" cycles, the box was very unstable.
 2 GB is barely enough for ZFS + NFS + Samba + torrents + whatever.

Freddie Cash
fjwcash at gmail.com

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