Gluster users - Jan 2014 - gluster replacing a brick

Hi folks,

Is there an easy way to shrink the size of a gluster volume by replacing
some of its constituent disks, and moving the data to other constituent
disks?

I did

gluster volume replace-brick <volname> <old-brick> <new-brick>

where both <old-brick> and <new-brick> are part of the gluster
setup, but
it wouldn't let me do this complaining that:

Brick: <new-brick> not available. Brick may be containing or be contained
by an existing brick.

Can I remove the new-brick, wipe off the gluster artifacts [the trusted.XXX
parameters], and then do the replace-brick? Will that cause any data loss?

Thanks,
Hari
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> From: "Hariharan Thantry" <thantry at gmail.com>
> To: gluster-users at gluster.org
> Sent: Friday, January 31, 2014 4:23:03 AM
> Subject: [Gluster-users] gluster replacing a brick
> Hi folks,
> Is there an easy way to shrink the size of a gluster volume by replacing
some
> of its constituent disks, and moving the data to other constituent disks?
Wouldn't remove-brick suffice for what you have in mind?
I would think you need to remove-bricks and rebalance to get the data migrated
out of the removed bricks, and then decommission those bricks (commit the
remove-brick).
> I did
> gluster volume replace-brick <volname> <old-brick>
<new-brick>
> where both <old-brick> and <new-brick> are part of the gluster
setup, but it
> wouldn't let me do this complaining that:
> Brick: <new-brick> not available. Brick may be containing or be
contained by
> an existing brick.
So <new-brick> is part of the same gluster volume, and hence the error
(even if it was part of another gluster volume the same would happen)
> Can I remove the new-brick, wipe off the gluster artifacts [the trusted.XXX
> parameters], and then do the replace-brick? Will that cause any data loss?
<new-brick> is part of the gluster volume, so wiping off gluster artefacts
would in turn result in data loss, or rather gluster failing to see this brick
as a part of the volume etc.
> Thanks,
> Hari