Restrictions

Do not use merge in combination with snapshots. Merging two regions can cause data loss if snapshots or cloned tables exist for this table.

If you have enabled the AccessController Coprocessor for HBase, only a global administrator can take, clone, or restore a snapshot, and these actions do not capture the ACL rights. This means that restoring a table preserves the ACL rights of the existing table, and cloning a table creates a new table that has no ACL rights until the administrator adds them.
Do not take, clone, or restore a snapshot during a rolling restart. Snapshots require RegionServers to be up; otherwise, the snapshot fails.
note
This restriction also applies to a rolling upgrade, which can be done only through Cloudera Manager.

If you are using HBase Replication and you need to restore a snapshot:

If you are using HBase replication, the replicas will be out of sync when you restore a snapshot. If you need to restore a snapshot, proceed as follows:

Disable the table that is the restore target, and stop the replication.
Remove the table from both the master and worker clusters.
Restore the snapshot on the master cluster.
Create the table on the worker cluster and use CopyTable to initialize it.