From: NeilBrown <neilb@suse.de>
To: shamim <shamim_99@yahoo.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: grow MULTIPATH RAID
Date: Fri, 25 Mar 2011 16:29:16 +1100 [thread overview]
Message-ID: <20110325162916.0c47ec71@notabene.brown> (raw)
In-Reply-To: <loom.20110325T041239-956@post.gmane.org>
On Fri, 25 Mar 2011 03:13:41 +0000 (UTC) shamim <shamim_99@yahoo.com> wrote:
> Hello Experts,
>
> Please help me to grow MULTIPATH RAID.
> My problem:
> I've Linux box which have MULTIPATH RAID created on them. Now we need to remove
> those old LUN and move data onto new LUN presented to those boxes.
>
> My initially thought was to grow the current MULTIPATH RAID (/dev/md0) and
> make old LUN as spare and then failed and then remove(Is this a right
> approach?). When I’m try adding new LUNs to it, they are getting added as spare
> ( as shown below). And when I try to grow , it refuse to do so. Below are the
> steps that I performed and error message.(Cannot reshaped!!)
> ( I read somehwere that we can’t grow MULTIPATH RAID, if it is TRUE, then what
> would be suggested solution to move data from old LUNs to new LUNs)
> Please help
No, you cannot grow an md/multipath device.
However you can simply create a new multipath config across
the set of paths that you want to use.
mdadm --stop /dev/md0
mdadm --create /dev/md0 --l multipath -n 4 ..list..of..paths...
However I recommend that you stop using md/multipath and look in to
using dm-multipath instead. See the 'multipath' command.
dm-multipath is actively developed. md/multipath is not.
NeilBrown
> --------------------------------------------------
>
> # mdadm --detail /dev/md0
> /dev/md0:
> Version : 0.90
> Creation Time : Thu Mar 24 13:54:41 2011
> Raid Level : multipath
> Array Size : 10486016 (10.00 GiB 10.74 GB)
> Raid Devices : 2
> Total Devices : 4
> Preferred Minor : 0
> Persistence : Superblock is persistent
>
> Update Time : Thu Mar 24 13:54:41 2011
> State : clean
> Active Devices : 2
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 2
>
> UUID : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Events : 0.3
>
> Number Major Minor RaidDevice State
> 0 65 0 0 active sync /dev/sdq
> 1 8 96 1 active sync /dev/sdg
> --------------------------------------------------------------------
> # mdadm /dev/md0 --add /dev/sdr /dev/sdh
> mdadm: added /dev/sdr
> mdadm: re-added /dev/sdh
>
> --------------------------------------------------------------------
> # mdadm --detail /dev/md0
> /dev/md0:
> Version : 0.90
> Creation Time : Thu Mar 24 13:54:41 2011
> Raid Level : multipath
> Array Size : 10486016 (10.00 GiB 10.74 GB)
> Raid Devices : 2
> Total Devices : 4
> Preferred Minor : 0
> Persistence : Superblock is persistent
>
> Update Time : Thu Mar 24 13:54:41 2011
> State : clean
> Active Devices : 2
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 2
>
> UUID : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Events : 0.3
>
> Number Major Minor RaidDevice State
> 0 65 0 0 active sync /dev/sdq
> 1 8 96 1 active sync /dev/sdg
>
> 2 65 16 - spare /dev/sdr
> 3 8 112 - spare /dev/sdh
>
> --------------------------------------------------------------------
> # mdadm --grow /dev/md0 --raid-disks=4
> mdadm: multipath array /dev/md0 cannot be reshaped.
>
>
>
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next prev parent reply other threads:[~2011-03-25 5:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-25 3:13 grow MULTIPATH RAID shamim
2011-03-25 5:29 ` NeilBrown [this message]
2011-03-25 6:06 ` Roberto Spadim
2011-03-25 6:21 ` NeilBrown
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