Using Metro Mirror primary volume during fast replication backup

You can use the FRBACKUP to PPRC Primary Volumes allowed field in the SMS copy pool definition panel to indicate whether a PPRC primary volume is an eligible FlashCopy® target, and whether a preserve mirror operation is required, preferred, or not desired when the target volume is a Metro Mirror primary volume during backup processing.

If you specify a value in the FRBACKUP to PPRC Primary Volumes allowed field, the value specified is considered in selecting FlashCopy target volumes for FRBACKUP processing during volume pairing. Otherwise, if you do not specify a value, DFSMShsm uses the currently stored preserve mirror indicator for the copy pool. If no preserve mirror indicator is set for the copy pool, the default is NO.

If you specify a value in the FRRECOV to PPRC Primary Volumes allowed field in the SMS copy pool definition panel, the L0 volumes are not examined for FlashCopy to Metro Mirror primary eligibility for FRRECOV processing during volume pairing. If preserve mirror is required during fast replication recovery using FlashCopy, you must ensure that your copy pool environment meets preserve mirror configuration requirements.

If preserve mirror is used in combination with incremental FlashCopy, the use of the PMPREF (preserve mirror preferred) or PMREQ (preserve mirror required) option needs to be consistent with the existing relationship when taking an increment. For example, if the existing incremental relationship was established without preserve mirror, an increment cannot be taken with the PMREQ option because the remote relationship will not exist and, therefore, an increment cannot be taken at the remote site. Do not change your preserve mirror settings between increments.

Note:
  1. A Metro Mirror primary volume is not allowed to be a FlashCopy target volume when:
    • NO is specified in the FRBACKUP to PPRC Primary Volumes allowed field
    • the NO option is in effect by default
    • the capability is not supported by the storage controller
  2. Specifying PMNO, PMPREF, or PMREQ in the FRBACKUP to PPRC Primary Volumes allowed field does not guarantee that a Metro Mirror primary volume is selected. You can ensure that a Metro Mirror primary volume is selected by ensuring that only Metro Mirror primary volumes exist in the copy pool backup storage group to be used.
  3. When you specify PMNO or PMPREF in the FRBACKUP to PPRC Primary Volumes allowed field, use SETSYS FASTREPLICATION(DATASETRECOVERY(NONE)) to prevent the source (L0) volume from going into a duplex pending state during the recovery of an individual data set from disk.
  4. The preserve mirror operation cannot be used in combination with fast reverse restore. Do not specify PMPREF or PMREQ in the FRBACKUP to PPRC Primary Volumes allowed or FRRECOV to PPRC Primary Volumes allowed fields for a copy pool defined allowing fast reverse restore.
  5. The preserve mirror operation cannot be used in combination with space efficient FlashCopy. When you specify PMPREF or PMREQ in the FRBACKUP to PPRC Primary Volumes allowed field, space efficient volumes are not eligible FlashCopy targets.
  6. When in a mixed release environment, releases prior to z/OS® V1R11 specify the ALLOWPPRCP settings on the FRBACKUP command. z/OS V1R11 will always use the SMS values first. If the value has been set in the SMS copy pool definition in z/OS V1R11, the DFSMShsm setting will be updated and the lower release hosts will use that value.

Related reading

Parent topic: Creating a fast replication backup