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Obsolete Releases => SME Server 7.x => Topic started by: william_syd on August 03, 2007, 11:26:34 AM

Title: Adding RAID Hot Spare after install?
Post by: william_syd on August 03, 2007, 11:26:34 AM

SME7.2

It appears that installing with three drives makes one a hot spare.

How do you add a hot spare after you have installed with two drive?

What 'triggers' a fall over to the spare and how automatic is it?

Title: Adding RAID Hot Spare after install?
Post by: Gert on August 04, 2007, 10:15:04 PM

Here's how to ass a hot spare:

http://prefetch.net/blog/index.php/2007/03/11/adding-a-hot-spare-to-an-md-device/

Title: Adding RAID Hot Spare after install?
Post by: william_syd on August 05, 2007, 02:49:23 AM

Thanks Gert.

I was looking for a "one click" solution within SME.

Next best is the add_drive_to_raid command. I'm not sure how it works with a 'hot' spare though. Time to play in a VM.

Code: [Select]

[root@tiger ~]# cat /sbin/e-smith/add_drive_to_raid
#!/usr/bin/perl -w
#----------------------------------------------------------------------
# add_drive_to_raid: Add spare disk to existing raid arrays
#----------------------------------------------------------------------
# Copyright (C) 2005 Gordon Rowell <gordonr@gormand.com.au>
# Copyright (C) 2006 Shad L. Lords <slords@mail.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
#----------------------------------------------------------------------


Title: Adding RAID Hot Spare after install?
Post by: william_syd on August 05, 2007, 02:55:57 AM

Oh.. one more question,

Does drive interface affect hot spare operation?

Title: Adding RAID Hot Spare after install?
Post by: TrevorB on August 05, 2007, 04:54:36 AM

Quote from: "william_syd"

Does drive interface affect hot spare operation?

No, but size does matter (ie. the new drive has to be => existing, if > anly the existing size will be used).

Also the script looks to do all the right things (although it fails on trying to put grub info on the new disk - but I don't think this is a problem in a hot-spare....).

Quote from: "william_syd"

What 'triggers' a fall over to the spare and how automatic is it?

A failure of any of the other drives in the raid group. And it is totally automagic (if you have a spare :-)).

Trevor B

Title: Adding RAID Hot Spare after install?
Post by: william_syd on August 05, 2007, 09:47:45 AM

Thanks Trevor.

Looks like that script does the trick...

Code: [Select]

[root@sme-raid ~]# mdadm -Ebsc partitions
ARRAY /dev/md1 level=raid1 num-devices=2 spares=1 UUID=b6a6096f:a8585d75:d3aaaffb:e42ad2e2
ARRAY /dev/md2 level=raid1 num-devices=2 spares=1 UUID=253ff517:44d4b41c:edf3babe:5b5d62d1
[root@sme-raid ~]#