You can use image mode volumes to import and then migrate existing data that is managed by an external storage system into the system.
You can either use the command line interface (CLI) to migrate data from external storage systems or use the Storage Migration wizard in the management GUI. The Storage Migration wizard simplifies the process by creating the image mode volume of the migrated data, host objects, host mappings, and moving that volume to a storage pool to be managed by the system.
Two connection types are supported to migrate data from external storage to the system. The Storage Migration wizard in the management GUI provides a complete list of prerequisites and environment modifications that are required to migrate data for each connection type.
Fibre Channel or Fibre Channel over Ethernet (FCoE) connections require that the SAN environment is zoned correctly. All host operations must be stopped on the external storage system before migration. Any environment-specific variables must also be changed.
For SAS attached external storage systems, the system supports wide port SAS connections and requires that the external storage system is directly attached to the system. As with Fibre Channel and FCoE connection, migrating data from SAS-attached external storage to the system requires stopping all host operations and modification of some environment settings.
To establish SAS connections, all Lenovo Storage V series systems can support an optional 4-port 12 Gbps SAS host interface adapter. Lenovo Storage V3700 V2 XP systems also have two onboard SAS ports (port 2 and 3) that can be used. For information about migration scenarios, see the Migrating topics.
The Storage Migration wizard guides you through the appropriate changes to the system. After migration completes, you must remove the external storage system from the system by using the appropriate method for each supported connection type.
If the existing storage systems do not follow the configuration guidelines, consider completing the data migration away from the image mode volume before you resume I/O operations on the host systems. If I/O operations are continued and the storage system does not follow the guidelines, I/O operations can fail at the hosts. Ultimately, you can lose access to the data.
The procedure for importing managed disks (MDisks) that contain existing data depends on the amount of free capacity that you have in the system. You must have the same amount of free space in the system as the size of the data that you want to migrate into the system. If you do not have this amount of available capacity, the migration causes the storage pool to have an uneven distribution of data because some MDisks are more heavily loaded than others. Further migration operations are required to ensure an even distribution of data and subsequent I/O loading.
When importing an image mode volume that has a certain amount of gigabytes and your system has at least that amount in a single storage pool, follow the Start New Migration wizard in the management GUI. Select to import the image mode volumes and to provide an even distribution of data.
When importing an image mode volume that has a certain amount of gigabytes and your system does not have at least that amount of free capacity in a single storage pool, follow the Start New Migration wizard in the management GUI. Select to import the image mode volumes. Do not select the destination pool at the end of the wizard. If the destination pool is selected, the system creates the image mode volumes but does not migrate the data away from the image mode volumes. Use volume mirroring or migration to move the data around as you want.