Prepping for a GFS2 Cluster
Hi Experts,
I currently have one server connected to a SAN, with the intention of purchasing an additional server within the next year. I'd like to setup a GFS2 cluster but the current RHEL6 doesn't support single-node GFS2. What can I do to build this architecture with the least amount of pain when I add the second server and want to configure GFS2? Or will I really need to reformat all the filesystems to get them into a cluster later?
Anyone have any suggestions?
Thanks,
Jeff Turmelle
International Research Institute for Climate and Society
Earth Institute, Columbia University
Responses
Hello Jeff, my name is Justin and a cluster specialist in Red Hat Support.
While we don't support single node gfs2 clusters, it is possible to do what you ask. You can create a gfs2 filesystem and mount it with lock=nolock. This will allow you to use it without the cluster infrastructure, on a single node only. Later, when you get your additional nodes you can remove that mount option, configure the cluster, and mount the filesystem on both nodes. Customers often use this feature to make backups of gfs2 filesystems from SAN snapshots without impacting performance. That's what this article is about:
How do I mount a GFS2 filesystem without starting the cluster services in Red Hat Enterprise Linux? - Red Hat Customer Portal
https://access.redhat.com/site/solutions/321503
You can skip the vgchange, as your volume group won't have the cluster flag (initially). You'll just want to mount with lock=nolock. Just because it can't be stressed enough, this will only allow for mounting from a single node. If you mount with multiple nodes with lock=nolock you run the risk of filesystem corruption.
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