freebsd stable - Sep 2008 - recommended setup for amd64 7-STABLE with ZFS, Samba 3.2 and possibly ACLs?

Hi,

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)
- Samba 3.2
  + ACLs possible directly under ZFS?
  + recommended compile options?
- NFS
- email (imap)
- jails (I have seen some problems exist with using snaphots within
  jails)

This is on amd64 with 8GB RAM and external disk array (via FC).

Many thanks and best regards,
Holger

--
Sorry - lost my signature somewhere. Need to buy a new one. Ofers?

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:

vm.kmem_size="1536M"
vm.kmem_size_max="1536M"
vfs.zfs.arc_min="16M"
vfs.zfs.arc_max="64M"
vfs.zfs.prefetch_disable="1"

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.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |

Holger Kipp wrote:
> - FreeBSD 7-Stable (amd64 with 8GB RAM)
>   + special tuning necessary (apart from increasing kernel memory
>     to 1 or more GB for ZFS)
I haven't had much luck running ZFS under heavy load on 7-stable, I was 
forced to install 8-current and use the latest patch set posted by pjd. 
  Don't jump in until you've tested it with a realistic production load.

The nice thing was that 8-current didn't require any special kernel or 
memory tuning at all (except for disabling ZIL, but not everyone seems 
to have to do this).
> - Samba 3.2
>   + ACLs possible directly under ZFS?
As far as I know ZFS does not support ACLs under FreeBSD at this time, 
and implementing it is non-trivial.

- Andrew

On 30 sep 2008, at 12:46, Jeremy Chadwick wrote:
> On Tue, Sep 30, 2008 at 12:08:48PM +0200, Holger Kipp wrote:
>> - 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).
I had to disable mmap access in dovecot, or it would coredump  
periodically. (mmap_disable = yes in dovecot.conf) I found that to be  
a problem only on ZFS. I don't know if that's been fixed yet. Apart  
from that it works great.

Ben