Placement group count for small clusters

Small clusters don’t benefit from large numbers of placement groups, therefore it is important to use the PG calculator with small clusters.

As the number of OSDs increase, choosing the correct value for pg_num and pgp_num becomes more important because it has a significant influence on the behavior of the cluster as well as the durability of the data when something goes wrong (that is the probability that a catastrophic event leads to data loss).

For more information about the PG calculator, see Placement group calculator.