From: Kyle Moffett <mrmacman_g4@mac.com>
To: Neil Brown <neilb@suse.de>
Cc: John Hendrikx <hjohn@xs4all.nl>,
linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org,
"Steinar H. Gunderson" <sgunderson@bigfoot.com>
Subject: Re: [PATCH 000 of 5] md: Introduction
Date: Sun, 22 Jan 2006 20:54:04 -0500 [thread overview]
Message-ID: <E47F8910-F8E6-4F64-90F0-3A13DF01F6AE@mac.com> (raw)
In-Reply-To: <17364.12454.643875.626906@cse.unsw.edu.au>
On Jan 22, 2006, at 20:25, Neil Brown wrote:
> Changing the size of the devices is a separate operation that has
> been supported for a while. For each device in turn, you fail it
> and replace it with a larger device. (This means the array runs
> degraded for a while, which isn't ideal and might be fixed one day).
>
> Once all the devices in the array are of the desired size, you run
> mdadm --grow /dev/mdX --size=max
> and the array (raid1, raid5, raid6) will use up all available space
> on the devices, and a resync will start to make sure that extra
> space is in-sync.
One option I can think of that would make it much safer would be to
originally set up your RAID like this:
md3 (RAID-5)
__________/ | \__________
/ | \
md0 (RAID-1) md1 (RAID-1) md2 (RAID-1)
Each of md0-2 would only have a single drive, and therefore provide
no redundancy. When you wanted to grow the RAID-5, you would first
add a new larger disk to each of md0-md2 and trigger each resync.
Once that is complete, remove the old drives from md0-2 and run:
mdadm --grow /dev/md0 --size=max
mdadm --grow /dev/md1 --size=max
mdadm --grow /dev/md2 --size=max
Then once all that has completed, run:
mdadm --grow /dev/md3 --size=max
This will enlarge the top-level array. If you have LVM on the top-
level, you can allocate new LVs, resize existing ones, etc.
With the newly added code, you could also add new drives dynamically
by creating a /dev/md4 out of the single drive, and adding that as a
new member of /dev/md3.
Cheers,
Kyle Moffett
--
I lost interest in "blade servers" when I found they didn't throw
knives at people who weren't supposed to be in your machine room.
-- Anthony de Boer
next prev parent reply other threads:[~2006-01-23 1:54 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-17 6:56 [PATCH 000 of 5] md: Introduction NeilBrown
2006-01-17 6:56 ` [PATCH 001 of 5] md: Split disks array out of raid5 conf structure so it is easier to grow NeilBrown
2006-01-17 14:37 ` John Stoffel
2006-01-19 0:26 ` Neil Brown
2006-01-21 3:37 ` John Stoffel
2006-01-22 22:57 ` Neil Brown
2006-01-17 6:56 ` [PATCH 002 of 5] md: Allow stripes to be expanded in preparation for expanding an array NeilBrown
2006-01-17 6:56 ` [PATCH 003 of 5] md: Infrastructure to allow normal IO to continue while array is expanding NeilBrown
2006-01-17 6:56 ` [PATCH 004 of 5] md: Core of raid5 resize process NeilBrown
2006-01-17 6:56 ` [PATCH 005 of 5] md: Final stages of raid5 expand code NeilBrown
2006-01-17 9:55 ` Sander
2006-01-19 0:32 ` Neil Brown
2006-01-17 8:17 ` [PATCH 000 of 5] md: Introduction Michael Tokarev
2006-01-17 9:50 ` Sander
2006-01-17 11:26 ` Michael Tokarev
2006-01-17 14:03 ` Kyle Moffett
2006-01-19 0:28 ` Neil Brown
2006-01-17 16:08 ` Ross Vandegrift
2006-01-17 18:12 ` Michael Tokarev
2006-01-18 8:14 ` Sander
2006-01-18 9:03 ` Alan Cox
2006-01-19 0:22 ` Neil Brown
2006-01-19 9:01 ` Jakob Oestergaard
2006-01-17 22:38 ` Phillip Susi
2006-01-17 22:57 ` Neil Brown
2006-01-17 14:10 ` Steinar H. Gunderson
2006-01-22 4:42 ` Adam Kropelin
2006-01-22 22:52 ` Neil Brown
2006-01-23 23:02 ` Adam Kropelin
2006-01-23 1:08 ` John Hendrikx
2006-01-23 1:25 ` Neil Brown
2006-01-23 1:54 ` Kyle Moffett [this message]
2006-01-17 21:38 Lincoln Dale (ltd)
2006-01-18 13:27 ` Jan Engelhardt
2006-01-18 23:19 ` Neil Brown
2006-01-19 15:33 ` Mark Hahn
2006-01-19 20:12 ` Jan Engelhardt
2006-01-19 21:22 ` Lars Marowsky-Bree
2006-01-19 22:17 ` Phillip Susi
2006-01-19 22:32 ` Neil Brown
2006-01-19 23:26 ` Phillip Susi
2006-01-19 23:43 ` Neil Brown
2006-01-20 2:17 ` Phillip Susi
2006-01-20 10:53 ` Lars Marowsky-Bree
2006-01-20 12:06 ` Jens Axboe
2006-01-20 18:38 ` Heinz Mauelshagen
2006-01-20 22:09 ` Lars Marowsky-Bree
2006-01-21 0:06 ` Heinz Mauelshagen
2006-01-20 18:41 ` Heinz Mauelshagen
2006-01-20 17:29 ` Ross Vandegrift
2006-01-20 18:36 ` Heinz Mauelshagen
2006-01-20 22:57 ` Lars Marowsky-Bree
2006-01-21 0:01 ` Heinz Mauelshagen
2006-01-21 0:03 ` Lars Marowsky-Bree
2006-01-21 0:08 ` Heinz Mauelshagen
2006-01-21 0:13 ` Lars Marowsky-Bree
2006-01-23 9:44 ` Heinz Mauelshagen
2006-01-23 10:26 ` Lars Marowsky-Bree
2006-01-23 10:38 ` Heinz Mauelshagen
2006-01-23 10:45 ` Lars Marowsky-Bree
2006-01-23 11:00 ` Heinz Mauelshagen
2006-01-23 12:54 ` Ville Herva
2006-01-23 13:00 ` Steinar H. Gunderson
2006-01-23 13:54 ` Heinz Mauelshagen
2006-01-23 17:33 ` Ville Herva
2006-01-24 2:02 ` Phillip Susi
2006-01-20 16:48 Hubert Tonneau
2006-01-20 17:01 Hubert Tonneau
2006-01-20 16:15 ` Christoph Hellwig
2006-01-22 6:45 ` Herbert Poetzl
2006-01-20 18:05 Hubert Tonneau
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