About Recovering Data in an Adabas Cluster
Point-in-time (incremental) data recovery refers to recovery of data changes up to a given point in time. Typically, you perform this type of recovery after restoring a full backup (adabck dump/restore). The full backup brings the cluster node to its state at the time the backup was created. Point-in-time recovery then updates the node incrementally from the time of the the full backup to a more recent time.
In an Adabas cluster, you can recover files or data on top of the last backup via the Adabas data protection log (PLOG).
Each node in a cluster writes its own PLOG data. You can rebuild a node by restoring the backup of the primary node and applying the PLOGs created by each node. The backup run by the SST does not generate a PLOG switch.
Whenever the primary node starts a new PLOG, all other nodes also start a new PLOG. These PLOGs have different numbers. When a new PLOG is started on a secondary node by adaopr, adabck or via restart, the other nodes don’t start a new PLOG. As a result, the content of the PLOGs that were created on different nodes are not necessarily identical. Either the session number is not common to all nodes in a cluster or several PLOGs on a secondary correspond to one PLOG on the primary node.
When you add a node to a cluster, back up the primary node so that the backup copy matches the local PLOG.
Note:
You might experience changes in performance when using the Adabas data protection log.
For more information about the Adabas data protection log, see the Adabas for Linux and Cloud documentation.