From owner-freebsd-stable@FreeBSD.ORG Thu Jul 9 13:21:55 2009
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
by hub.freebsd.org (Postfix) with ESMTP id 95F061065687
for <freebsd-stable@freebsd.org>; Thu, 9 Jul 2009 13:21:55 +0000 (UTC)
(envelope-from tonix@interazioni.it)
Received: from mx02.interazioni.net (mx02.interazioni.net [80.94.114.204])
by mx1.freebsd.org (Postfix) with ESMTP id BBAB28FC08
for <freebsd-stable@freebsd.org>; Thu, 9 Jul 2009 13:21:54 +0000 (UTC)
(envelope-from tonix@interazioni.it)
Received: (qmail 72601 invoked by uid 88); 9 Jul 2009 13:21:52 -0000
Received: from unknown (HELO ?192.168.56.198?)
(tonix@interazioni.it@85.18.206.139)
by relay.interazioni.net with ESMTPA; 9 Jul 2009 13:21:52 -0000
Message-ID: <4A55EEEC.3030007@interazioni.it>
Date: Thu, 09 Jul 2009 15:21:48 +0200
From: "Tonix (Antonio Nati)" <tonix@interazioni.it>
User-Agent: Thunderbird 2.0.0.22 (Windows/20090605)
MIME-Version: 1.0
To: freebsd-stable@freebsd.org
References: <20090709112512.GA44158@hugo10.ka.punkt.de> <73a41d4b72d62b0bfe3d0fb7206376a8.squirrel@cygnus.homeunix.com>
<20090709123434.GC46563@hugo10.ka.punkt.de>
In-Reply-To: <20090709123434.GC46563@hugo10.ka.punkt.de>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-Content-Filtered-By: Mailman/MimeDel 2.1.5
Subject: Re: ZFS - thanks
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
<mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
<mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Thu, 09 Jul 2009 13:21:55 -0000
Patrick M. Hausen ha scritto:
> Hello,
>
> On Thu, Jul 09, 2009 at 09:17:35AM -0300, Nenhum_de_Nos wrote:
>
>
>>> So now we have this setup:
>>>
>>> NAME STATE READ WRITE CKSUM
>>> zfs ONLINE 0 0 0
>>> raidz2 ONLINE 0 0 0
>>> label/disk100 ONLINE 0 0 0
>>> label/disk101 ONLINE 0 0 0
>>> label/disk102 ONLINE 0 0 0
>>> label/disk103 ONLINE 0 0 0
>>> label/disk104 ONLINE 0 0 0
>>> label/disk105 ONLINE 0 0 0
>>> raidz2 ONLINE 0 0 0
>>> label/disk106 ONLINE 0 0 0
>>> label/disk107 ONLINE 0 0 0
>>> label/disk108 ONLINE 0 0 0
>>> label/disk109 ONLINE 0 0 0
>>> label/disk110 ONLINE 0 0 0
>>> label/disk111 ONLINE 0 0 0
>>>
>>> which will get another enclosure with 6 750-GB-disks, soon.
>>>
>
>
>> I've always been curious about this. is said not good to have many disks
>> in one pool. ok then. but this layout you're using in here will have the
>> same effect as the twelve disks in only one pool ? (the space here is the
>> sum of both pools ?)
>>
>
> It is not good to have too many disks in one group. What you see
> above is one pool with two raidz2 groups.
>
> As far as I understood the documentation after that helpful
> comment on this list, this is the recommended configuration.
>
> -------------------------------
> http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide
>
> "The recommended number of disks per group is between 3 and 9.
> If you have more disks, use multiple groups."
> -------------------------------
>
> The result is, of course, one big pool with lots of storage
> space, but the overhead necessary for redundancy is roughly
> twice that of my "dangerous" twelve-disk configuration.
>
> So I lost the equivalent of two disks or about 1 TB here.
> Fast, reliable, cheap - pick any two ;-)
>
> Kind regards,
> Patrick
>
I see a lot of people advicing to use ZFS RAID instead of HW RAID.
I'm going to use HP duplicated iSCSI subsystems, which have autonomous
RAID, so I'm confused about this advice.
Following the ZFS RAID stream, should I keep each disk alone in iSCSI
and let the ZFS make the RAID job?
Should not HW RAID to be (a lot) more efficient?
Which would be the wrong side of using HW RAID with ZFS?
Thanks,
Tonino
--
------------------------------------------------------------
Inter@zioni Interazioni di Antonio Nati
http://www.interazioni.it tonix@interazioni.it
------------------------------------------------------------