Reverting a 3-site consistency group to a 2-site consistency group

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You can take an existing 3-site consistency group and convert it to a 2-site consistency group for both Metro Mirror or HyperSwap® configurations.

Orchestrator 4.0 supports the ability to remove a relationship that contains data from an existing 3-site consistency group and revert it to a 2-site independent relationship. For more information, see Removing and reverting relationship from 3-site consistency group.

When you convert the 3-site consistency group to a 2-site consistency group, replication occurs between the near sites only. Any replication of data to the auxiliary-far site is stopped and the volumes on the system at auxiliary-far site become available for host operations. To convert a 3-site consistency group to a 2-site consistency group, you must ensure that the following condition is met:
  • The 3-site consistency group must be in stopped or partial state.

Using the management GUI

If the 3-site consistency group is not in the stopped state, complete these steps:
  1. In the management GUI, select Copy Services > Remote Copy > 3-site partnership to view the 3-site consistency groups in the partnership.
  2. Select the 3-site consistency group and Actions > Stop group.
  3. After the state of 3-site consistency group changes to stopped, select Actions > Revert to 2-site.
  4. Select Revert.

    Select the 3-site consistency group and verify that all its relationships display in the list of relationships.

If the 3-site consistency group is in the partial state, complete these steps:
  1. Select the 3-site consistency group and Actions > Revert to 2-site.
  2. Select Revert.

    If the operation does not complete fully, select the 3-site consistency group and select Actions > Revert again. You can select Resume conversion to 3-site to return the configuration back to a 3-site configuration.

Using the command-line interface

A partial state can occur during the configuration of 3-site replication or if the Orchestrator experiences a failure. In the case where 3-site consistency group is in the partial state, you do not need to stop replication. If other errors occur during the process, they must be resolved before you resume the conversion. If the state of 3-site consistency group is any other state but partial, you must stop the 3-site consistency group. To convert a 3-site consistency group to a 2-site consistency group, complete these steps:
  1. If the 3-site consistency group is in a state other than partial, enter the following command:
    stop3sitercconsistgrp rccstgrp15
    where rccstgrp15 is the name of the 3-site consistency group.
  2. To verify that the 3-site consistency group is stopped, enter the following command:
    # ls3sitercconsistgrp
name       state            primary periodic_copy_source sync_copy_state         periodic_copy_state freeze_time         cycle_period status
rccstgrp14 3site_consistent Master  Auxnear              consistent_synchronized stopped             2022/01/20/18/24/03 300          online
rccstgrp15 stopped          Master  Auxnear              consistent_synchronized idling              2022/01/19/18/42/58 300          online
  3. To convert all the relationships in the 3-site consistency group to a 2-site consistency group between the near sites, enter the following command:
    convertrcconsistgrp -type 2site rccstgrp15
If the conversion completes successfully, verify that the 3-site consistency group no longer displays by entering the following command: 
# ls3sitercconsistgrp
name       state            primary periodic_copy_source sync_copy_state         periodic_copy_state freeze_time         cycle_period status
rccstgrp14 3site_consistent Master  Auxnear              consistent_synchronized stopped             2022/01/20/18/24/03 300          online
In this example, the rccstgrp15 no longer displays in the results.
If errors occur in the conversion process, ensure that errors are resolved and rerun the convertrcconsistgrp command.
Note: If the operation takes too much time, the convertrcconsistgrp command fails with a timeout error. The error message CMMVC5762E The request did not complete before the timeout period expired is returned. Fix any reported errors and re-run the convertrcconsistgrp command.