Disaster recovery from the primary site (PPRC multi-target) by incremental resync

True Copy for Mainframe User Guide for VSP One Block 85

Version

10.5.x

File Size

2745 KB

Audience

anonymous

Part Number

MK-26VSP1B036-02

ft:lastEdition

2026-06-23

Operations can be continued by using the volumes at the secondary sites with duplicating data when the primary site fails in a PPRC multi-target configuration with an MTIR pair. Switch operations from the primary site to a secondary site first if the primary site fails. The following procedure assumes that site A is the primary site, and sites B and C are secondary sites in a PPRC multi-target configuration. The procedure describes how to resume business at site B and restore the DR duplex configuration.

Confirm that an MTIR pair exists between site B and site C.
At site B, note the TCz pair status and fence level of the volume that is paired with the TCz volume at site A.
At site B, confirm data in the volume is guaranteed by the pair status and the fence level. See Checking S-VOL consistency with the P-VOL.
For pairs whose P-VOL fence level is set to never, further analysis is required to determine the volume consistency. This can be determined by using sense information transferred by host failover or by comparing the contents of the volume with other files that are confirmed to be consistent (for example, database log files). The volume should be recovered using the files that are confirmed to be consistent.
Recover files if necessary.
At site A, perform the Freeze command on both pairs in the secondary sites.
Go to next step if the Freeze command fails when the site A failure is serious.
At site A, perform the Run command on both pairs in the secondary sites.
Go to next step if the Run command fails when the site A failure is serious.
At site B, perform the Failover command on the TCz volume that is paired with TCz volume in site A.
Confirm all recovery operations are completed at site B before varying the TCz volumes paired with site A online.
If IPL in the secondary host is required, perform the following procedures.
1. Contact maintenance personnel and complete remote copy SIMs before performing OS IPL.
2. Perform IPL in the secondary host.
3. Vary the volume online after IPL is completed.
  Perform this step when the volume is not varied online automatically.
Resume operations at site B.

If you want to duplicate data before resuming business, perform steps 10a through 10c before you resume business at site B.
Perform the following steps only when an MTIR pair exists between site B and site C.
1. At site C, perform Failover to the TCz volume that is paired with site A.
2. From site B, perform Failback (incremental resync) to the TCz volume that is paired with site C in MTIR. The full copy of the data is required in a pair that does not support the differential data copy function in the PPRC multi-target configuration, while only the differential data is copied in a supported pair. The full copy of the data is required in a pair that shares volumes with unsupported and supported pairs for differential data copy function in the PPRC multi-target configuration.
  The copy pace during the incremental resync operation might be slower than initial copy because incremental resync acts the same as pair resync operation.
3. Confirm that the status of the MTIR pair has changed to Duplex.
4. At site B, perform Failback to the TCz volume that is paired with site A after site A is recovered from the failure.
  This operation changes the configuration to PPRC multi-target with site B as the primary. An MTIR pair is created between site A and site C.

After you have completed this procedure, site B becomes the primary site in the PPRC multi-target configuration.

To change the PPRC multi-target configuration back to the original PPRC multi-target configuration (site A as the primary site and site B as the secondary site), perform this procedure using site B as the primary site.