Restore the data in a cluster from the stored backups.
You can restore data to a cluster from local keyspace backups and backups stored to cloud
storage providers like Amazon S3. These restores can be from a particular point-in-time if you
enabled commitlog backups.
When performing a restore operation, you can restore all the keyspaces from a backup or select
specific keyspaces and tables.
Note: Restoring a snapshot that contains only the system keyspace is not allowed. There must be both system and non-system keyspaces,
or only non-system keyspaces in the snapshot you want to restore.
When restoring from backups stored on Amazon S3, OpsCenter chooses an agent to determine which
nodes in the cluster have data that needs to be restored. The SSTables stored in the S3 bucket
are sorted into directories with the node ID of the original node. If the cluster topology is
unchanged from when the backup was taken, OpsCenter instructs each node to restore the set of
SSTables that were stored on that node before. If the cluster topology has changed since the
backup was completed, OpsCenter attempts to match the SSTables to the node that originally stored
the SSTable, and distributes the remaining SSTables to the remaining nodes to distribute the load
evenly.
Note: The Restore feature of the Backup Service leverages the sstableloader utility,
which currently requires enabling the thrift server on all nodes before restoring.
If you are doing a point-in-time restore, your cluster topology must not have changed since the
backup. Attempting to perform a point-in-time restore on a cluster whose topology has changed
results in a failure. DataStax recommends performing a snapshot backup before changing cluster
topology. You can then restore the cluster based on that backup.