Hello,
We have a Moodle 2.6 cluster with the webroot/ moodledata in a NFS share (v3).
We are considering moving it to NFS v4, so we need to know if there's some considerations to be aware of, or Moodle (in cluster) doesn't care about it.
Best regards,
Ricardo Santos
Hi Ricardo,
Moodle will be happier with v4 for its better file locking management which is a key point for the MUC infrastructure with the default setup, unless you're already using something like memcached for the cache stores.
HTH,
Matteo
Hey Matteo,
First of all, thanks for the feedback.
Indeed we are using memched but we can reevaluate its need. Do we need to make some kind of Moodle reconfig in order to use NFS v4 or it's strait forward (i.e. just umount and mount again in nfs v4)?
Regards,
Ricardo
Hi Ricardo,
it's just unmount/remount: Moodle is agnostic but the need to exclusively lock files when writing/updating some of them.
Please follow Anna Jonna Ármannsdóttir's advices, as part of a good fs tuning job: Moodle has no requirements here but file locking and a file system with "nice" IOPS.
HTH,
Matteo
I assume this means moving from NFS v3 to NFS v4. In that case you might use the opportunity to check if you are using the optimum block size in the mount parameters. In my case I found considerable increase in throughput by first finding the optimum block size and then setting it in the mount options. I used IOZone to test this:
./iozone -Racb moodlecl22nfsmoodle.wks -g 1G -y 1 -q 128k -i0 -i1 -U /mnt/lms/moodle -f /mnt/lms/moodle/iozone/prufuskra.bin
Found that the optimum block size was 16 KB and set the mount parameters accordingly:
mount -o rw,vers=4,addr=1.2.3.4,clientaddr=1.2.3.10,nodiratime,noatime,rsize=16384,wsize=16384 /mnt/lms/moodle
You also might want to check that the TCP and UDP packets from the NFS connection, are not obstructed by firewalls. That kills performance.
