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Subject: Re: ZFS confusion
From: Dennis Glatting <freebsd@penx.com>
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On Mon, 2014-01-27 at 10:20 +0000, Steve O'Hara-Smith wrote:
> On Mon, 27 Jan 2014 09:59:27 +0000
> Kaya Saman <kayasaman@gmail.com> wrote:
> 
> > Would it be better to create a raidz1 pool then just add raidz1 pools to 
> > the master as time goes by?
> 
> 	I would advise against using any scheme that only allows a single
> disc failure. When (not if) a disc fails and needs to go RMA you're stuck
> with no redundancy at all until the replacement comes back and gets
> resilvered. That can be an uncomfortably long time, especially if all your
> drives came from the same batch (if at all possible don't let that happen,
> I've seen a big RAID array lose several drives in one day because they all
> came from the same batch and all wore out together).
> 

+1

I've been burned by multiple drive failures more times than I care to
admit. Most of my RAID arrays are now RAID6 or RAIDz2. I mirror when I
have small space requirements (storage and physical) and I'm satisfied
with the risk.