[Gluster-users] Restore a node in a replicating Gluster setup after data loss

[Niklaus Hofer]

Hi

We have a Replica 2 + Arbiter Gluster setup with 3 nodes Server1, 
Server2 and Server3 where Server3 is the Arbiter node. There are several 
Gluster volumes ontop of that setup. They all look a bit like this:

gluster volume info gv-tier1-vm-01

[...]
Number of Bricks: 1 x (2 + 1) = 3
[...]
Bricks:
Brick1: Server1:/var/data/lv-vm-01
Brick2: Server2:/var/data/lv-vm-01
Brick3: Server3:/var/data/lv-vm-01/brick (arbiter)
[...]
cluster.data-self-heal-algorithm: full
[...]

We took down Server2 because we needed to do maintenance on this 
server's storage. During maintenance work, we ended up having to 
completely rebuild the storage on Server2. This means that 
"/var/data/lv-vm-01" on Server2 is now empty. However, all the Gluster 
Metadata in "/var/lib/glusterd/" is still in tact. Gluster has not been 
started on Server2.

Here is what our sample gluster volume currently looks like on the still 
active nodes:

gluster volume status gv-tier1-vm-01

Status of volume: gv-tier1-vm-01
Gluster process                             TCP Port  RDMA Port  Online  Pid
------------------------------------------------------------------------------
Brick Server1:/var/data/lv-vm-01            49204     0          Y 
22775
Brick Server3:/var/data/lv-vm-01/brick      49161     0          Y 
15334
Self-heal Daemon on localhost               N/A       N/A        Y 
19233
Self-heal Daemon on Server3                 N/A       N/A        Y 
20839


Now we would like to rebuild the data on Server2 from the still in tact 
data on Server1. That is to say, we hope to start up Gluster on Server2 
in such a way that it will sync the data from Server1 back. If at all 
possible, the Gluster cluster should stay up during this process and 
access to the Gluster volumes should not be interrupted.

What is the correct / recommended way of doing this?

Greetings
Niklaus Hofer
-- 
stepping stone GmbH
Neufeldstrasse 9
CH-3012 Bern

Telefon: +41 31 332 53 63
www.stepping-stone.ch
niklaus.hofer at stepping-stone.ch