XRC support
TDMF allows a volume that is the primary in an XRC session to be specified as a source or target volume for a Swap or Point-In-time migration. Restrictions on the use of an XRC active source volume in a Swap migration are listed below.
- TDMF allows a swap migration source volume to be active in an XRC
session to a non-mirrored target device, if the
XRCVolumeoption was specified (see Volume options.) With Release 5.2.0, TDMF allows the XRC migration session's Data Mover address space to be active on the same LPAR as the TDMF Master job or on an Agent LPAR. In this situation, the target device must be XRC capable. Also, TDMF will use theXDELPAIRand XADDPAIR commands to reestablish the XRC session for the volume (on the target device) after the swap. You need to make sure that the target device is compatible with the existing XRC session's Utility devices. For more information, see the DFSMS Advanced Copy Services manual. - For users who run the System Data Mover on the remote system, TDMF allows only the migration of
XRC volumes to mirrored devices (for example, PPRC, SRDF, and XRC). The
ALLOWmirrorchangeoption must be supplied for the volume if the target device is not being mirrored by XRC. For more information, see Common options for the SESSION, GROUP, MIGRATE, and REPLICATE statements.
When you swap to a target volume that is active in an XRC session, validate that the System Data
Mover detected the change of volume serial number. For example, by using the TSO command
XQUERY target_volume_XRC_session VOLUME(source_volume). The XRC device
pair remains mirrored, even if the SDM did not detect the change of volume serial. Obviously, the
disaster recovery procedures for the source volume serial must be amended to address the XRC
secondary device, as in every migration to a mirrored target device.
TDMF writes to an XRC target volume as fast as it can, which means that care must be taken when you migrate multiple volumes into the same XRC session. Judicious use of the concurrent volume limit might be required to prevent the XRC link from being overloaded by the TDMF volume copy phase.