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Most of these benefits also apply to migration efforts controlled by the customer when utilizing TDMF or FDRPAS in customer-managed systems.

Piper for z/OS is an IGS service offering which relieves the customer of the actual migration process and requires customer involvement only in the planning and preparation phase. The actual migration is transparent to the customer’s application hosts and Piper even manages a concurrent switch-over to the target volumes. Piper is neutral to the disk storage vendors and works for all devices supported under z/OS or OS/390.

Data migration with z/OS Global Mirror

Another alternative is z/OS Global Mirror (XRC). XRC is an asynchronous solution that has a mode for disaster recovery (DR) solutions as well as a particular migration mode of SESSIONTYPE(MIGRATE). This mode does not require the customer to plan for a JOURNALs configuration at the secondary site, which is mandatory for DR solutions based on XRC.

	Production systems
ANTAS001	OS/390
ANTAS002	zOS
ANTAS003	zLINUX
	zVM no minidisks
ANTAS004
	VSE/ESA
ANTAS004
	ESCON / FICON
	Director

Source			Target
	Primary	Secondary	Disk
Disk
			Servers
subsystems	Volume	Volume

SDM LPAR

XRECOVER XRECOVER

SDM1

SDM3

SDM2

SDM4

SDM5

XRECOVER

XRECOVER XRECOVER

Figure 14-3 Data Migration with z/OS Global Mirror (XRC)

XRC allows for an online data migration approach, which is almost non-disruptive. The application only needs to shut down for the actual switch to the target volumes in the new disk storage server. It can restart immediately to connect to the new disk storage server after the XRC secondary volumes have been relabeled by a single XRC command per XRC session,

XRECOVER.

In addition to transparent data replication, the advantage of XRC is extreme scalability. Figure 14-3shows that XRC can run either in existing system images or in a dedicated LPAR. Each image can host up to five System Data Movers (SDM). An SDM is an address space (ANTAS00x) that is started by a respective XSTART command. A reasonable number of XRC volume pairs that a single SDM can manage is in the range of 1,500 to 2,000 volume pairs. With up to five SDMs within a system image, this totals approximately 10,000 volume pairs.

Chapter 14. Data migration in zSeries environments 301