Home > Storage > PowerMax and VMAX > Mainframe > Dell PowerMax: Data Protector for z Systems (zDP) Best Practices > Overview
We recommend the following zDP operational best practices:
Define a zDP VDG that aligns with the SRDF groups. With SRDF groups, only create groups if required since it is easier to manage fewer groups.
Consider using the NOSORT attribute when creating and adding devices (MODIFY,ADD) to the VDG and TGT to avoid zDP changing the SOURCE-to-TARGET pair relationship. Specify NOSORT to ensure that zDP maintains the required SOURCE-to-TARGET mapping. Without NOSORT, zDP does not always obey the specified sequence of devices that are added to the VDG and TGT. The result could cause unpredictable UCB mapping. For example, not following this process can cause confusion where a customer believes that the RES volume is at one UCB, and when the LINK occurred without NOSORT specified, zDP linked the RES volume to a different UCB address.
While zDP is active within SCF, SRDF actions (SC commands) are blocked because zDP puts a lock on the devices. Stop zDP to perform host-component SC commands. A sample stop command is as follows:
‘/F <scf address space>,ZDP STOP <vdg name>’
With Mainframe Enablers versions before 8.4, zDP definitions do not persist beyond IPLs. The snapshots persist, but the VDG and TGT definitions and device lists do not. These definitions must be re-created and MODIFIED, and devices must be added after an IPL. As of MFE 8.5, customers can preserve the zDP VDG and TGT definitions to avoid having to re-create and modify VDGs and TGTs after an IPL. If you have MFE versions 8.4 or earlier, stop zDP before performing an IPL for the controlling LPAR and re-creating the VDG and TGT definitions.