Introduction to migrating using partition mirroring

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Partition mirroring uses host-based storage replication technology to copy SYSBAS from the source node to the copy node.

Advantages of partition mirroring

Migrating using partition mirroring has several key advantages:

  • No initial outage on the source node is needed because the creation of install media or user data save media is not necessary.

  • The host-based storage replication occurs below the technology-independent machine interface (TIMI) so there are no locking considerations or conflicts with on-going production workloads.

  • Because the storage replication processing occurs within the IBM® i operating system, partition mirroring can be used with any storage technology.

  • Test mode is available, which allows the user to freely and fully evaluate the copy node before finalizing the migration.

  • The status and progress of partition mirroring is easy to observe, monitor, and estimate from within the Db2® Mirror GUI.

Limitations of partition mirroring

The following environments are not supported by partition mirroring.

  • If the source node contains an encrypted user auxiliary storage pool (ASP), it is not eligible for partition mirroring.

  • If the source node contains independent ASPs (IASPs), the IASPs will not be replicated using partition mirroring.

Partition mirroring migration timeline

The following steps describe the timeline for a migration using partition mirroring.

  1. Decide whether the existing IBM i (source node) will be used as the Db2 Mirror graphical user interface (GUI) node.

  2. Install the required products and the latest level of PTF groups on the source node and GUI node.

  3. Install IBM i License Internal Code (LIC) on the IBM i that will be the target of the migration (copy node).

  4. Establish and start partition mirroring.

    At this point, storage is being asynchronously replicated from the source node to the copy node.

    Figure 1. Migrate While Active – Partition Mirroring
    Migrate While Active – Partition Mirroring

  5. After the full synchronization of storage completes, partition mirroring continues to migrate storage as changes are made on the source node.

  6. Optionally, the Migrate While Active user can decide to transition into test mode. During test mode, the user can bring the copy node up to a usable state and conduct any testing or usage scenarios. Figure 2 and Figure 3 depict two usages of test mode.

    Figure 2. Partition mirroring test mode with active source node
    Partition mirroring test mode with active source node
    Figure 3. Partition mirroring test mode with inactive source node
    Partition mirroring test mode with inactive source node

  7. After exiting test mode, resuming partition mirroring data replication will bring the copy node back into sync with the storage on the source node. The tracked changes on the copy node are undone and then the tracked changes on the source node are migrated. The migration of these tracked changes is depicted in Figure 4.

    Figure 4. Migrating tracked changes using partition mirroring
    Migrating tracked changes using partition mirroring

  8. When the Migrate While Active user is ready to complete the migration to the copy node, a final cutover is performed to complete the migration to the copy node.