Home > Storage > PowerMax and VMAX > Mainframe > Dell PowerMax: Data Protector for z Systems (zDP) Essentials > How does zDP work?
zDP runs within the Mainframe Enablers Resource Pak Base in a z/OS environment. The zDP application automates the creation of consistent snapshots on a continuous basis. zDP uses a construct called a ‘Versioned Data Group’ (VDG) that defines the source volumes used for the point-in-time copies. These source volumes can be referred to by SYMM ID, z/OS device number, SCF Group Name Services (GNS) group name, or volume serial number. When the customer starts the VDG through EMCSCF address space, the source volumes defined in that VDG are used to create “snapsets”. When the maximum number of snapsets is reached, zDP terminates the oldest snapset within the VDG (based on MAX_SNAPSETS parameter setting).
To link the entire snapset to a group of target volumes, the user must define a set of target volumes within zDP called the Target Set. Note that a zDP Target Set does not need to be defined for zDP to operate and to take snapsets. However, in order to use the data from a snapset you must link the snapset to the Target Set from within zDP or link individual snapshots from the snapset to target volumes using the EMCSNAP batch utility. Finally, while zDP runs, you can use the zDP Versioned Data Group (VDG) query commands to monitor and report on the zDP application.