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Date: Wed, 19 Feb 2014 10:11:11 +1100
From: andrew clarke <mail@ozzmosis.com>
To: freebsd@fongaboo.com
Subject: Re: ZFS on Hardware RAID controller
Message-ID: <20140218231111.GB90045@ozzmosis.com>
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Cc: questions@freebsd.org, Eitan Adler <eadler@freebsd.org>
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On Tue 2014-02-18 17:27:52 UTC-0500, freebsd@fongaboo.com (freebsd@fongaboo.com) wrote:

> When we spoke, you noted that when installing ZFS on multiple disks 
> connected to a hardware RAID controller, it is best to config it to JBOD.
> 
> I tried to explain this to a colleague, but they were skeptical. Would you 
> (or anyone) be willing to give me a one or two line sales-pitch on why one 
> should abandon traditional notions of RAID performance in favor of 
> allowing ZFS to do disk management?

Without JBOD, the hardware RAID appears to FreeBSD as a single disk.
There is little to nothing to be gained from running ZFS on a single
disk. Without JBOD, should a disk in the RAID fail, "zpool status"
won't be able to tell you which one.

Regards
Andrew