Data migration

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The system allows you to migrate data across MDisks without interfering with any host applications that are simultaneously accessing or writing data.

During data migration, host applications can continue to access and use volume data as if no data migration were occurring.

Data migration applications

Data migration has the following characteristics and applications:
  • Changes the MDisks to which the volume is allocated.
  • Does not disrupt access to the volume data.
  • Can be used when you are removing MDisks from a clustered system.
  • Can move data to an MDisk that has appropriate performance for host requirements.
  • Can move data from image mode volumes to MDisks when you are adding a system to an existing SAN infrastructure.
  • Can migrate striped and sequential volumes to an image mode volume.

Non-disruptive system migration

The system supports non-disruptive system migration, which allows volume data to be migrated using remote copy functions to another system. To use this feature you do not need a remote copy license to create and manage these migration. Both the management GUI and command-line interface support migrating volume data between systems non-disruptively. The non-disruptive system migration is a remote-copy relationship type that is dedicated to volume migration between systems.

With non-disruptive system migration, storage administrators can migrate volumes from one IBM Spectrum Virtualize system to another without any application downtime. This function supports a number of use cases. For example, you can use this function to balance the load between multiple systems or to update and decommission hardware. You can also migrate data between node-based systems and enclosure-based systems. Unlike replication remote-copy types, non-disruptive system migration does not require a Remote Mirroring license before you can configure a remote-copy relationship that is used for migration.

However, remote-copy relationships that are used for migration have the following restrictions:
  • Stop-with-access is prohibited. The volumes cannot act independently if they are using the same UUID.
  • Migration relationships cannot be added to a consistency group.
  • You cannot change the relationship to another type of remote-copy relationship.
  • Migration relationship cannot be converted into a 3-site relationship.
  • Associating change volumes to a migration relationship is prohibited.
  • Volumes in migration relationships cannot be resized until the migration is completed or canceled.
  • ODX must be disabled on both systems while migrating volumes.
    Note: If ODX is disabled, it cannot be re-enabled on the 8.4.2 software. Currently ODX support is not available on 8.4.2.
  • Migration of volumes that are mapped to NVMe-attached hosts is not supported.
  • Migration of SAN-boot volumes is not supported.

For more information, see Migrating data between systems non-disruptively.