Default data replicas

The default replication factor for data blocks may be specified at file system creation by using the -r option on the mmcrfs command or changed at a later time by using the -r option on the mmchfs command.

This value must be equal to or less than MaxDataReplicas, and the value cannot exceed the number of failure groups with disks that can store data. The allowable values are 1, 2, and 3, with a default of 1 (no replication).

If you want to change the data replication factor for the entire file system, the data disk in each storage pool must have a number of failure groups equal to or greater than the replication factor. For example, you will get a failure with error messages if you try to change the replication factor for a file system to 2 but the storage pool has only one failure group.