Checksum protection guards against data loss on any disk in an auxiliary storage pool (ASP).
The checksum software maintains a coded copy of ASP data in special checksum data areas within that ASP. Any changes made to permanent objects in a checksum protected ASP are automatically maintained in the checksum data of the checksum set. If any single disk unit in a checksum set is lost, the server reconstructs the contents of the lost device using the checksum and the data on the remaining functional units of the set. In this way, if any one of the units fails, its contents can be recovered. This reconstructed data reflects the most up-to-date information that was on the disk at the time of the failure. Checksum protection can affect server performance significantly. In a distributed relational database, this might be a concern.