Questions about OCFS2: How to span local partitions, journaling, lvm2-lock, clvm, etc.


consummate homelabber
Mar 17, 2017
Near Seattle

curious about how to get distributed volumes to span several devices. Unfortunately haven't seen much literature about this.

I'm actually using Ubuntu instead of Oracle Linux, but the setup procedure appears virtually identical. Here's what I'm following, which seems to be the best lit. I found so far regarding OCFS2 setup: Oracle® Linux 8 Managing Shared File Systems - Chapter 3 Managing the Oracle Cluster File System Version 2 in Oracle Linux:

The ocfs2 setup manuals I've seen instruct people to create a partition, make the ocfs2 filesystem, and mount the drive. Then, the cluster.conf setup allows the systems specified to communicate and replicate data across the filesystem. But what if I want to add more than one partition on each node? Unfortunately, that doesn't appear to be mentioned.

I was thinking maybe I'd have to use something like lvm to create a logical volume. I know ocfs2 is not lvm-aware, but I assume something like lvm2-lock or clvm, which are meant for cluster LVs, could be applicable?

The other thing I'm wondering about is using an NVMe drive for cache - does OCFS2 have a convenient way to do this? I see:

-J size=journal-size

--journal-options size=journal-size
Which look kind of like what I'm looking for, but how could I put a write-ahead journal on another drive? Or, is there any adaptive read cache?

If anyone has more experience with this, I'd love to hear from you. Thanks :)