METHOD AND APPARATUS FOR REPLICATING THE PUNCH COMMAND

The punch command may be replicated in a replication environment including a production site and a replication site. The solution includes implementing a punch command to free storage received at a replication site in a replication environment by applying the punch command to storage at the replication site and writing data being freed from the storage at the replication site to an undo stream of a journal at the replication site. If the punch command is not supported, a command to write zeros may be used. Further, an unpunch command is provided for properly undoing a punch command and storing data written to the volume before the punch command freed the storage. Additionally, large punch commands may be split into a plurality to smaller punch commands for efficient journal management. Additionally, volume space may be reclaimed by writing a punch command to the journal instead of zeros.