Linux Btrfs filesystem development
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From: Russell Coker <russell@coker.com.au>
To: Zack Coffey <clickwir@gmail.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: RAID1 3+ drives
Date: Sat, 28 Jun 2014 10:51 +1000	[thread overview]
Message-ID: <10572318.CAuhDIAMDU@xev> (raw)
In-Reply-To: <CAA8KC9J4M+Vsk0Wjs+vbgQVrcgMfznwE9WwqapHKhH82g_-hBA@mail.gmail.com>

On Fri, 27 Jun 2014 20:30:32 Zack Coffey wrote:
> Can I get more protection by using more than 2 drives?
> 
> I had an onboard RAID a few years back that would let me use RAID1
> across up to 4 drives.

Currently the only RAID level that fully works in BTRFS is RAID-1 with data on 
2 disks.  If you have 4 disks in the array then each block will be on 2 of the 
disks.  RAID-5/6 code mostly works but the last report I read indicated that 
some situations for recovery and disk replacement didn't work - presumably 
anyone who's afraid of multiple disks failing isn't going to want to trust 
BTRFS RAID-6 code at the moment.

If you want to have 4 disks in a fully redundant configuration (IE you could 
lose 3 disks without losing any data) then the thing to do is to have 2 RAID-1 
arrays with Linux software RAID and then run BTRFS RAID-1 on top of that.

-- 
My Main Blog         http://etbe.coker.com.au/
My Documents Blog    http://doc.coker.com.au/


  reply	other threads:[~2014-06-28  0:51 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-28  0:30 RAID1 3+ drives Zack Coffey
2014-06-28  0:51 ` Russell Coker [this message]
2014-06-28  4:26   ` Duncan
2014-06-28  6:28     ` Russell Coker
2014-06-28  7:38       ` Martin Steigerwald
2014-06-28  7:43         ` Hugo Mills
2014-06-28 11:38       ` Duncan
2014-06-28 13:40         ` Russell Coker
2014-06-28 18:15       ` Chris Murphy
2014-06-28 10:13     ` Roman Mamedov
2014-06-29  2:30       ` Duncan

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