From: sam tygier <samtygier@yahoo.co.uk>
To: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 0/5] [RFC] RAID-level terminology change
Date: Sun, 10 Mar 2013 23:55:10 +0000 [thread overview]
Message-ID: <khj6gq$nan$1@ger.gmane.org> (raw)
In-Reply-To: <1362861071-12589-1-git-send-email-hugo@carfax.org.uk>
On 09/03/13 20:31, Hugo Mills wrote:
> Some time ago, and occasionally since, we've discussed altering the
> "RAID-n" terminology to change it to an "nCmSpP" format, where n is the
> number of copies, m is the number of (data) devices in a stripe per copy,
> and p is the number of parity devices in a stripe.
>
> The current kernel implementation uses as many devices as it can in the
> striped modes (RAID-0, -10, -5, -6), and in this implementation, that is
> written as "mS" (with a literal "m"). The mS and pP sections are omitted
> if the value is 1S or 0P.
>
> The magic look-up table for old-style / new-style is:
>
> single 1C (or omitted, in btrfs fi df output)
> RAID-0 1CmS
> RAID-1 2C
> DUP 2CD
> RAID-10 2CmS
> RAID-5 1CmS1P
> RAID-6 1CmS2P
Are these the only valid options? Are 'sensible' new levels (eg 3C, mirrored to 3 disk or 1CmS3P, like raid6 with but with 3 parity blocks) allowed? Are any arbitrary levels allowed (some other comments in the thread suggest no)? Will there be a recommended (or supported) set?
next prev parent reply other threads:[~2013-03-10 23:55 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-09 20:31 [PATCH 0/5] [RFC] RAID-level terminology change Hugo Mills
2013-03-09 20:31 ` [PATCH 1/5] Use nCmSpP format for mkfs Hugo Mills
2013-03-09 20:31 ` [PATCH 2/5] Move parse_profile to utils.c Hugo Mills
2013-03-09 20:31 ` [PATCH 3/5] Convert balance filter parser to use common nCmSpP replication-level parser Hugo Mills
2013-03-09 20:31 ` [PATCH 4/5] Change output of btrfs fi df to report new (or old) RAID names Hugo Mills
2013-03-09 20:31 ` [PATCH 5/5] Add man page description for nCmSpP replication levels Hugo Mills
2013-03-10 14:01 ` Goffredo Baroncelli
2013-03-10 17:20 ` Hugo Mills
2013-03-10 17:52 ` Goffredo Baroncelli
2013-03-09 21:38 ` [PATCH 0/5] [RFC] RAID-level terminology change Harald Glatt
[not found] ` <CAFWF=am4ki529Zez4123gYk3BD+Z9RONRpAK7NZe=skHzcdMiw@mail.gmail.com>
2013-03-09 21:46 ` Hugo Mills
2013-03-09 22:25 ` Roger Binns
2013-03-10 1:44 ` Hugo Mills
2013-03-10 5:41 ` Roger Binns
2013-03-10 6:29 ` Harald Glatt
2013-03-10 6:37 ` Harald Glatt
2013-03-10 11:31 ` Martin Steigerwald
2013-03-10 11:48 ` Roger Binns
2013-03-10 22:04 ` Hugo Mills
2013-03-11 0:21 ` Roger Binns
2013-03-27 4:27 ` Brendan Hide
2013-03-27 5:24 ` Roger Binns
2013-03-10 11:23 ` Martin Steigerwald
2013-03-10 14:11 ` Goffredo Baroncelli
2013-03-10 21:36 ` Hugo Mills
2013-03-10 21:45 ` Harald Glatt
2013-03-10 22:59 ` Goffredo Baroncelli
2013-03-10 22:06 ` Harald Glatt
2013-03-10 23:06 ` Diego Calleja
2013-03-10 15:43 ` Goffredo Baroncelli
2013-03-10 22:24 ` Hugo Mills
2013-03-10 22:42 ` Harald Glatt
2013-03-10 23:40 ` sam tygier
2013-03-10 23:49 ` Hugo Mills
2013-03-11 14:14 ` David Sterba
2013-03-10 23:55 ` sam tygier [this message]
2013-03-11 8:56 ` Hugo Mills
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