[Gluster-users] Upgrading ancient gluster version

[Dave Warren]

I'm finally hoping to be able to upgrade a relatively ancient gluster 
3.4.2 on Ubuntu 14.04 to a more modern version of Gluster and want to 
verify that I am prepared.

I currently have two gluster servers and hope to have all volumes in a 
mirror configuration prior to upgrading. There are various clients, most 
of which I can directly control. We do not currently use quota or 
geo-replication, which I understand should simplify the process.

First off, what version should I be targeting? The goal (aside from 
being up to date) is small file performance. From what I have read, the 
best option is to use the PPA at https://launchpad.net/~gluster/, is 
that still correct?

I'm not certain if I can get the clients to all shut down and 
disconnect, if not, will it hurt me if 3.4.2 clients are attempting to 
connect? I will be scheduling a maintenance window and could firewall 
them off until they're upgraded if needed. From reading 
https://gluster.readthedocs.org/en/latest/Upgrade-Guide/Upgrade%20to%203.7/ 
in the "Pre-upgrade" section it looks like I should probably firewall 
off clients until I confirm they're upgraded, is that correct?

Finally, what is the rollback procedure if I encounter problems? Can I 
revert to the old version of gluster and use my existing bricks?

Is there anything else I should be aware of, or any significant changes 
that are likely to cause issues other than the upgrade process itself?

-- 
Dave Warren
http://www.hireahit.com/
http://ca.linkedin.com/in/davejwarren