recommended setup for amd64 7-STABLE with ZFS, Samba 3.2 and possibly ACLs?

Jeremy Chadwick koitsu at
Tue Sep 30 10:46:06 UTC 2008

On Tue, Sep 30, 2008 at 12:08:48PM +0200, Holger Kipp wrote:
> could anyone give recommendations (or share experience) regarding 
> using ZFS:  
> - FreeBSD 7-Stable (amd64 with 8GB RAM)
>   + special tuning necessary (apart from increasing kernel memory
>     to 1 or more GB for ZFS)

Applicable loader.conf variables which should suffice:


You can increase arc_max gradually, and performance should increase as
you do so.  Just be aware that too large of a value could result in kmem
exhaustion on RELENG_7.

There is a 2GB limit on kmem on RELENG_7 (yes, both i386 AND amd64), so
do not try to increase vm.kmem_size or kmem_size_max above what I've
shown there (others may have chosen something slightly higher, but
picking 2048M will cause the system not to boot).  If the limit is a
problem, consider running CURRENT which increases this to 512GB.

The prefetch setting should improve overall system performance during
heavy ZFS load; many of us (including core members) have found this to
be true.

> - email (imap)

I've had good experience with dovecot; I tend to stay away from Cyrus
products (disgusting code with a history of security issues), and
Courier (no interest).

| Jeremy Chadwick                                jdc at |
| Parodius Networking              |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |

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