Home > Storage > PowerMax and VMAX > Mainframe > Dell PowerMax: Data Protector for z Systems (zDP) Best Practices > Overview
When planning for a TimeFinder SnapVX and zDP implementation, storage space is the primary resource consideration. A PowerMax Storage Resource Pool (SRP) is a collection of disk groups that are configured into a thin-data pools. The default setting for the PowerMax back-end SRP pool reserve capacity (PRC) is 10%. When space consumption reaches the PRC (which is strictly used for new host writes), you cannot create snapshots, and existing nonsecure snapshots are failed. Due to this behavior, all SnapVX and zDP implementations should accommodate for at least some of the snapshots to be secure.
When the SRP is 100% full, SRDF replication stops if the array is an SRDF target. Also, all local host I/O stops, which has an operational impact. It is critical to design proper space alerting to warn customers well before the 90% SRP full is reached. Space-reclamation procedures should be well understood, tested, and documented to relieve the space shortage condition should they arise.
Space-reclamation procedures include the following: