< Previous  | TOC | Index | Next  >

Example 2—Migrating the Primary role in a setup with multiple Secondaries

We recommend that you create RLINKs between hosts london and tokyo when setting up the RDS.

  Note   Create SRLs of the same size on the Primary and Secondary hosts.

Before migration, the configuration of the RDS looks like this:

 To migrate the Primary RVG hr_rvg to host london

1. Stop the applications that use the Primary data volumes. For example, if the application is a file system, unmount it.
2. Verify that the Primary RLINKs are up-to-date by using the vxrlink status command. On the Primary seattle, issue the following commands:

   # vxrlink -g hrdg status rlk_london_hr_rvg

   # vxrlink -g hrdg status rlk_tokyo_hr_rvg

   The vradmin migrate command fails if the Primary RLINKs are not up-to-date or not in the connect state. It also fails if the data volumes are active.

3. Migrate the Primary RVG hr_rvg by typing the following command from any host in the RDS:

# vradmin -g hrdg migrate hr_rvg london

4. If you had created RLINKs between the Secondary london and the additional Secondary tokyo, host tokyo is automatically added to the new configuration.

   Otherwise, you must manually add tokyo as a Secondary to the new Primary london. To do this, create RLINKs between london and tokyo and associate them to the respective RVGs using the following commands.

   On host london:

   # vxmake -g hrdg rlink rlk_tokyo_hr_rvg local_host=london \

   remote_host=tokyo remote_rlink=rlk_london_hr_rvg \

   remote_dg=hrdg

   # vxrlink -g hrdg assoc hr_rvg rlk_tokyo_hr_rvg

   On host tokyo:

   # vxmake -g hrdg rlink rlk_london_hr_rvg local_host=tokyo \

   remote_host=london remote_rlink=rlk_tokyo_hr_rvg \

   remote_dg=hrdg

   # vxrlink -g hrdg assoc hr_rvg rlk_london_hr_rvg

   ---

     Note   By default, the vxmake rlink command creates the RLINK with the protocol set to UDP/IP. To change the protocol to TCP/IP, see Setting the network transport protocol.

   ---

5. Start replication to tokyo using the following command:

   # vradmin -g hrdg -f startrep hr_rvg tokyo

   ---

     Note   Ensure that the above command is run before starting the application on the new Primary london.

   ---

6. Restart the application.

   Because the application was stopped properly before the migration, an application recovery is not required.

   By default, the vradmin migrate command enables replication from the new Primary london. To start the application before enabling replication, first, issue the vradmin pauserep command, start the application, and then resume replication.

After migration, the configuration of the RDS looks like this: