mount – Mounting an ocfs2 partition (with multipath removed)

(I previously posted this on AskUbuntu, but I’ve since deleted that since no one replied and I now think it’s server-related and probably more suitable for here.)

I look after a set of servers running Ubuntu 20.04 which are attached to a disk array that has been formatted as an ocfs2 filesystem. I have been encountering a strange problem. The disk array has two network connections out to a router, so I have been using multipath on the servers. But, for two programs (at least) which output to both standard error and to a file, gibberish (i.e., non-ASCII characters) appear in standard error. The output file itself is fine (as far as I know). But this problem concerns me a bit…

When the same programs with the same inputs write to a externally mounted ext4 filesystem, this does not occur. As far as I can tell, the main difference between the two is the use of multipath. So…to test this “theory”, I’m now removing multipath on one server.

(Indeed, if this doesn’t solve the problem, then I will need to try something else.)

I disabled multipath by:

  1. Unmounted the array.
  2. Removed the multipath-tools package.
  3. Removed the entry in /etc/fstab.
  4. Rebooted.

When I restarted, I saw this in lsblk:

sdb      8:16   0  36.4T  0 disk 
├─sdb1   8:17   0  34.5T  0 part /data
└─sdb2   8:18   0   1.9T  0 part /home
sdc      8:32   0    53T  0 disk 
sde      8:64   0    53T  0 disk 

I guess I have never seen this before. sdb is an ext4 partition and it is fine. But how come the disk array appears as just disk. Underneath it, I don’t see partitions like sdc1.

In the /dev/ directory, I see this:

$ ls -al sdb*
brw-rw---- 1 root disk 8, 16 May 24 12:10 sdb
brw-rw---- 1 root disk 8, 17 May 24 12:10 sdb1
brw-rw---- 1 root disk 8, 18 May 24 12:10 sdb2
$ ls -al sdc*
brw-rw---- 1 root disk 8, 32 May 24 12:10 sdc

Does something have to be done on either the disk array or on the server? I was thinking of just trying mount.ocfs2 but I think I better seek opinions first. Without multipath, I’d probably just use one of the network connections now. i.e., sdc.

I tried the partprobe command and ran it with no changes. I then ran partprobe -s and it gave this output:

/dev/sdb: gpt partitions 1 2
/dev/sdc: msdos partitions

Does this mean I made a mistake in the very beginning and this disk array should have been made as a gpt partition? Is that why I don’t see part? But multipath works with “msdos partitions”?

What are my options? The partition currently has user data, so I’m hesitant to just trying to mount without asking for opinions. It’s only partially used, so I can probably find space to move files around to make room, if it is necessary.