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From: Neil Bothwick <neil@digimed.co.uk>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] Hard drive storage questions
Date: Tue, 28 Apr 2015 19:41:43 +0100	[thread overview]
Message-ID: <20150428194143.1e4534ea@digimed.co.uk> (raw)
In-Reply-To: <CAGfcS_=Yrkmc=+oDAY+vJaUUExL94QO7JfoDreKN3C1oJfFL7A@mail.gmail.com>

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On Tue, 28 Apr 2015 14:31:23 -0400, Rich Freeman wrote:

> >> btrfs raid5 is still fairly experimental (though now it supports
> >> recovery) and works more-or-less how you'd expect raid5 to work.
> >> Raid1 on btrfs gives you the capacity of n/2 and not n-1 disks,  
> >
> > You're right, I was clearly confused (an oxymoron?) when I wrote that.
> >
> > So RAID1 gives less capacity than RAID5 on BTRFS, but it is stable (in
> > btrfs terms).
> >  
> 
> For drives of identical size and not using compression, I'd expect
> space use on btrfs to be equivalent to the same raid level on
> mdadm+lvm+ext4.

That's only true for RAID1 when you have 2 drives, with more drives btrfs
gives more space.

3 x 2TB drives give 2TB on MD RAID1
3 x 2TB drives give 3TB on btrfs RAID1

Although you will get slightly less usable space with btrfs because of
the space used for metadata, but I'm not sure how significant that is.


-- 
Neil Bothwick

QOTD:
	The only easy way to tell a hamster from a gerbil is that the
	gerbil has more dark meat.

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  reply	other threads:[~2015-04-28 18:41 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-28  8:39 [gentoo-user] Hard drive storage questions Dale
2015-04-28 14:49 ` Francisco Ares
2015-04-28 15:01 ` Alan McKinnon
2015-04-28 15:24   ` Neil Bothwick
2015-04-28 17:38     ` Rich Freeman
2015-04-28 18:11       ` Neil Bothwick
2015-04-28 18:31         ` Rich Freeman
2015-04-28 18:41           ` Neil Bothwick [this message]
2015-04-28 22:02     ` [gentoo-user] " walt
2015-04-29  1:24       ` Rich Freeman
2015-04-29  6:20       ` Alan McKinnon
2015-04-29 14:31         ` Grant Edwards
2015-04-29  6:13     ` [gentoo-user] " Alan McKinnon
2015-04-29  7:52       ` Neil Bothwick
2015-05-04  7:39         ` Dale
2015-05-04  7:46           ` Neil Bothwick
2015-05-04  8:13             ` Mick
2015-05-04  8:26               ` Dale
2015-05-04  8:23             ` Dale
2015-05-04 10:31               ` Neil Bothwick
2015-05-04 10:40                 ` Dale
2015-05-04 11:26                   ` Neil Bothwick
2015-05-09 10:56                     ` Dale
2015-05-09 12:59                       ` Rich Freeman
2015-05-09 14:46                         ` Todd Goodman
2015-05-09 18:16                           ` Rich Freeman
2015-05-04 11:35                 ` Rich Freeman
2015-05-04 18:42                   ` Nuno Magalhães
2015-05-05  6:41                     ` Alan McKinnon
2015-05-05 10:56                     ` Rich Freeman
2015-05-05 11:33                       ` Neil Bothwick
2015-05-05 12:05                         ` Mick
2015-05-05 12:21                           ` Neil Bothwick
2015-05-05 12:39                             ` Mick
2015-05-05 12:53                             ` Rich Freeman
2015-05-05 21:50                               ` Neil Bothwick
2015-05-05 22:21                                 ` Bill Kenworthy
2015-05-05 22:33                                   ` Bill Kenworthy
2015-05-04 10:57               ` Alan Mackenzie
2015-04-28 15:02 ` Rich Freeman
2015-05-04  7:23 ` Dale
2015-05-05  3:01   ` Walter Dnes
  -- strict thread matches above, loose matches on Subject: below --
2018-11-09  1:16 Dale
2018-11-09  1:31 ` Jack
2018-11-09  1:43   ` Dale
2018-11-09  2:04     ` Andrew Lowe
2018-11-09  2:07     ` Bill Kenworthy
2018-11-09  8:39       ` Neil Bothwick
2018-11-09  2:29 ` Rich Freeman
2018-11-09  8:17   ` Bill Kenworthy
2018-11-09 13:25     ` Rich Freeman
2018-11-09  9:02   ` J. Roeleveld
2018-11-11  0:45   ` Dale
2018-11-11 21:41     ` Wol's lists
2018-11-11 22:17       ` Dale
2018-11-09  9:24 ` Wols Lists
2015-04-27  7:41 Dale
2015-04-28 18:25 ` Daniel Frey
2015-04-28 21:23   ` Dale

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