Configuring default placement group count

When you create a pool, you also create a number of placement groups for the pool. While Ceph uses the default value of 8, this should increased along with the default value.

If you don’t specify the number of placement groups, Ceph uses the default value of 8, which is unacceptably low. You can increase the number of placement groups for a pool, but we recommend setting reasonable default values too.

osd pool default pg num = 100
osd pool default pgp num = 100

You need to set both the number of placement groups (total), and the number of placement groups used for objects (used in PG splitting). They should be equal.