Managing Placement Groups
pg_num
Set number of placement groups:
kubectl rook-ceph ceph osd pool set $POOL_NAME pg_num $COUNT
kubectl rook-ceph ceph osd pool set $POOL_NAME pgp_num $COUNT
Setting the pg_num tells ceph how many PGs to divide the data into.
Setting the pgp_num tells ceph to actually rebalance and use all PGs.
The two values should be equal. $COUNT should be a power of 2. There should not be more than 100 PGs per OSD.