Getting this in a two node cluster?

volume set: failed: Quorum not met. Volume operation not allowed.

If you can't afford a third, you'll have to disable the quorum:

[root@mdskvm-p01 glusterfs]#
[root@mdskvm-p01 glusterfs]# gluster volume info

Volume Name: mdsgv01
Type: Replicate
Volume ID: f5b57076-dbd4-4d77-ae13-c1f3ee3adbe0
Status: Stopped
Snapshot Count: 0
Number of Bricks: 1 x 2 = 2
Transport-type: tcp
Bricks:
Brick1: mdskvm-p02.nix.mds.xyz:/mnt/p02-d01/glusterv02
Brick2: mdskvm-p01.nix.mds.xyz:/mnt/p01-d01/glusterv01
Options Reconfigured:
storage.owner-gid: 36
cluster.data-self-heal-algorithm: full
performance.low-prio-threads: 32
features.shard-block-size: 512MB
features.shard: on
storage.owner-uid: 36
cluster.server-quorum-type: server
cluster.quorum-type: auto
server.event-threads: 8
client.event-threads: 8
performance.write-behind-window-size: 8MB
performance.io-thread-count: 16
performance.cache-size: 1GB
nfs.trusted-sync: on
server.allow-insecure: on
performance.readdir-ahead: on
[root@mdskvm-p01 glusterfs]# gluster volume set mdsgv01 cluster.quorum-type none
volume set: success
[root@mdskvm-p01 glusterfs]#
[root@mdskvm-p01 glusterfs]# gluster volume set mdsgv01 cluster.server-quorum-type none
volume set: success
[root@mdskvm-p01 glusterfs]#

Do this on each node.  After this, start the cluster.

Cheers,
TK