How to Perform a Failback-Switchover on a System That Uses Hitachi TrueCopy Replication

Use this procedure to restart an application on the original primary cluster, cluster-paris, after the data on this cluster has been resynchronized with the data on the current primary cluster, cluster-newyork.

The failback procedures apply only to clusters in a partnership. You need to perform the following procedure only once per partnership.

Before You Begin

Before you perform a failback-switchover, a takeover has occurred on cluster-newyork. The clusters have the following roles:

• If the original primary cluster, cluster-paris, has been down, confirm that the cluster is booted and that the Sun Cluster Geographic Edition infrastructure is enabled on the cluster. For more information about booting a cluster, see Booting a Cluster in Sun Cluster Geographic Edition System Administration Guide.

• The protection group on cluster-newyork has the primary role.

• The protection group on cluster-paris has either the primary role or secondary role, depending on whether cluster-paris could be reached during the takeover from cluster-newyork.

1. Resynchronize the original primary cluster, cluster-paris, with the current primary cluster, cluster-newyork.

   cluster-paris forfeits its own configuration and replicates the cluster-newyork configuration locally. Resynchronize both the partnership and protection group configurations.

   1. On cluster-paris, resynchronize the partnership.

      phys-paris-1# geops update partnershipname

      partnershipname

      Specifies the name of the partnership

      ---

      Note –

      You need to perform this step only once per partnership, even if you are performing a failback-switchover for multiple protection groups in the partnership.

      ---

      For more information about synchronizing partnerships, see Resynchronizing a Partnership in Sun Cluster Geographic Edition System Administration Guide.

   2. On cluster-paris, resynchronize each protection group.

      Because the local role of the protection group on cluster-newyork is now primary, this steps ensures that the role of the protection group on cluster-paris becomes secondary.

      phys-paris-1# geopg update protectiongroupname

      protectiongroupname

      Specifies the name of the protection group

      For more information about synchronizing protection groups, see Resynchronizing a Hitachi TrueCopy Protection Group.

2. On cluster-paris, validate the cluster configuration for each protection group.

   Ensure that the protection group is not in an error state. A protection group cannot be started when it is in an error state.

   phys-paris-1# geopg validate protectiongroupname

   protectiongroupname

   Specifies a unique name that identifies a single protection group

   For more information, see How to Validate a Hitachi TrueCopy Protection Group.

3. On cluster-paris, activate each protection group.

   Because the protection group on cluster-paris has a role of secondary, the geopg start command does not restart the application on cluster-paris.

   phys-paris-1# geopg start -e local protectiongroupname

   -e local

   Specifies the scope of the command.

   By specifying a local scope, the command operates on the local cluster only.

   protectiongroupname

   Specifies the name of the protection group.

   ---

   Caution –

   Do not use the -n option because the data needs to be synchronized from the current primary, cluster-newyork, to the current secondary, cluster-paris.

   ---

   Because the protection group has a role of secondary, the data is synchronized from the current primary, cluster-newyork, to the current secondary, cluster-paris.

   For more information about the geopg start command, see How to Activate a Hitachi TrueCopy Protection Group.

4. Confirm that the data is completely synchronized.

   The state of the protection group on cluster-newyork must be OK.

   phys-newyork-1# geoadm status

   Refer to the Protection Group section of the output.

   The protection group has a local state of OK when the Hitachi TrueCopy device groups on cluster-newyork have a state of PVOL_PAIR and the Hitachi TrueCopy device groups on cluster-paris have a state of SVOL_PAIR.

5. On either cluster, perform a switchover from cluster-newyork to cluster-paris for each protection group.

   # geopg switchover [-f] -m clusterparis protectiongroupname

   For more information, see How to Switch Over a Hitachi TrueCopy Protection Group From Primary to Secondary.

   cluster-paris resumes its original role as primary cluster for the protection group.

6. Ensure that the switchover was performed successfully.

   Verify that the protection group is now primary on cluster-paris and secondary on cluster-newyork and that the state for Data replication and Resource groups is OK on both clusters.

   # geoadm status

   Check the runtime status of the application resource group and data replication for each Hitachi TrueCopy protection group.

   # scstat -g

   Refer to the Status and Status Message fields that are presented for the data replication device group you want to check. For more information about these fields, see Table 2–1.

   For more information about the runtime status of data replication see, Checking the Runtime Status of Hitachi TrueCopy Data Replication.