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From: Phillip Susi <psusi@ubuntu.com>
To: ashford@whisperpc.com,
	Jose Manuel Perez Bethencourt <jmperezbeth@gmail.com>
Cc: Chris Murphy <lists@colorremedies.com>,
	"sys.syphus" <syssyphus@gmail.com>,
	Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: I need to P. are we almost there yet?
Date: Tue, 30 Dec 2014 21:45:16 -0500	[thread overview]
Message-ID: <54A3633C.3040609@ubuntu.com> (raw)
In-Reply-To: <40b56c60ddd4801295a92c4b11d5c08e.squirrel@webmail.wanet.net>

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On 12/30/2014 06:17 PM, ashford@whisperpc.com wrote:
> I believe that someone who understands the code in depth (and that
> may also be one of the people above) determine exactly how BTRFS
> implements RAID-10.

I am such a person.  I had a similar question a year or two ago (
specifically about raid10  ) so I both experimented and read the code
myself to find out.  I was disappointed to find that it won't do
raid10 on 3 disks since the chunk metadata describes raid10 as a
stripe layered on top of a mirror.

Jose's point was also a good one though; one chunk may decide to
mirror disks A and B, so a failure of A and C it could recover from,
but a different chunk could choose to mirror on disks A and C, so that
chunk would be lost if A and C fail.  It would probably be nice if the
chunk allocator tried to be more deterministic about that.


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  reply	other threads:[~2014-12-31  2:48 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-29 18:56 I need to P. are we almost there yet? sys.syphus
2014-12-29 19:00 ` sys.syphus
2014-12-29 19:04   ` Hugo Mills
2014-12-29 20:25     ` sys.syphus
2014-12-29 21:50       ` Hugo Mills
2014-12-29 21:16   ` Chris Murphy
2014-12-30  0:20     ` ashford
     [not found]       ` <CALBWd85UsSih24RhwpmDeMjuMWCKj9dGeuZes5POj6qEFkiz2w@mail.gmail.com>
2014-12-30 17:09         ` Fwd: " Jose Manuel Perez Bethencourt
2014-12-30 21:44       ` Phillip Susi
2014-12-30 23:17         ` ashford
2014-12-31  2:45           ` Phillip Susi [this message]
2014-12-31 17:27             ` ashford
2014-12-31 23:38               ` Phillip Susi
2015-01-01  1:26               ` Chris Samuel
2015-01-01 20:12                 ` Roger Binns
2015-01-02  3:47                   ` Duncan
2015-01-02 13:42               ` Austin S Hemmelgarn
2015-01-02 17:45                 ` Brendan Hide
2015-01-02 19:41                   ` Austin S Hemmelgarn
2014-12-29 21:13 ` Chris Murphy
2015-01-03 11:34 ` Bob Marley
2015-01-03 13:11   ` Duncan
2015-01-03 18:53     ` Bob Marley
2015-01-03 19:03       ` sys.syphus
2015-01-03 18:55     ` sys.syphus
2015-01-04  3:22       ` Duncan
2015-01-04  3:54         ` Hugo Mills
2015-01-03 21:58     ` Roman Mamedov
2015-01-04  3:24       ` Duncan

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