[Gluster-users] Correct way to migrate brick to new server (Gluster 6.10)

[Ronny Adsetts]

Alex Wakefield wrote on 16/09/2020 06:33:
> 
> We have a distribute replicate gluster volume running Gluster 6.10 on
> Ubuntu 18.04 machines. Its a 2 x 2 brick setup (2 bricks, 2
> replicas).
> 
> We need to migrate the existing bricks to new hardware without
> downtime and are lost at whats the proper way to do it. I've found
> this post [1] which suggests that we can do a replace-brick command
> and move it to the new server without downtime but this [2]
> mailinglist thread suggests this isn't the correct way to do it
> anymore?
> 
> The gluster docs [3] have information for replacing _faulty_ bricks
> but our bricks aren't faulty, we just need to move them to new
> hardware. We've tried using this method mentioned in the docs in the
> past but have found that the volume gets into weird states where
> files go into read-only mode or have their permissions set to
> root:root. It basically plays havoc on the fs mount that the clients
> use.
> 
> Any help would be greatly appreciated. Apologies if I've left any
> information out.

Hi,

We had this same quandary in March[1]. We first tested using add-brick/remove-brick which resulted in permissions/ownership mayhem. After some head scratching, I took the replace-brick approach which worked fine.

Something like so for each brick, waiting for all heals to complete between brick replacements:

$ sudo gluster volume replace-brick volname stor-old-1:/data/glusterfs/volname/brick1/brick stor-new-1:/data/glusterfs/volname/brick1/brick commit force

I did this on a live volume starting with the data I cared about least first. Nerves were properly on edge for the first volume I can tell you! :-).

I would, if feasible, recommend doing a test migration on a small volume and checksum the data before and after.

Thanks.

Ronny

[1] https://lists.gluster.org/pipermail/gluster-users/2020-March/037786.html

-- 
Ronny Adsetts
Technical Director
Amazing Internet Ltd, London
t: +44 20 8977 8943
w: www.amazinginternet.com

Registered office: 85 Waldegrave Park, Twickenham, TW1 4TJ
Registered in England. Company No. 4042957


-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 195 bytes
Desc: OpenPGP digital signature
URL: <http://lists.gluster.org/pipermail/gluster-users/attachments/20200916/c7083b2a/attachment.sig>