Types of Data Migration

1 Overview of HP 3PAR Online Import for EMC Storage

HP 3PAR Online Import for EMC Storage manages the migration of data from a source EMC Storage system to a destination HP 3PAR StoreServ Storage system. Using HP 3PAR Online Import for EMC Storage, you can migrate EMC volumes and host configuration information to a destination HP 3PAR StoreServ Storage system without changing host configurations or interrupting data access. The terms storage system and array are used interchangeably throughout this guide, and may refer to either the EMC Storage or HP 3PAR StoreServ Storage systems. The source in the migration is the EMC Storage system, and the destination is the HP 3PAR StoreServ Storage system.

HP 3PAR Online Import for EMC Storage coordinates the movement of data from the source to the destination while servicing I/O requests from the hosts. During the data migration, host I/O is serviced from the destination HP 3PAR StoreServ Storage system. The host/volume presentation implemented on the EMC Storage is maintained on the destination HP 3PAR StoreServ Storage system.

The HP 3PAR Online Import Software supports three types of data migration procedures. The appropriate type of data migration depends on the objects being migrated and the migration type.

•Online—Migration type used when migrating a host or a volume presented to a host. During online migration, all presentation relationships between hosts and volumes being migrated are maintained. Host I/O to the data is not disrupted during an online migration.

•Minimally disruptive migration (MDM)—Migration type used when migrating a host or a volume presented to a host. Host I/O is interrupted only during the time it takes to reconfigure the host.

•Offline—Migration type used when migrating one or more unpresented volumes. During offline migration, only the selected volumes are migrated. No hosts are migrated in this situation.

For additional information about online migration, see the support matrix for online import for EMC Storage on HP SPOCK:

HP SPOCK (http://www.hp.com/storage/spock)

Understanding Which Data is Migrated

Data can be migrated by selecting a host or a volume on the source EMC Storage system. In addition to the host or volume explicitly selected for an online migration or for MDM, other objects can be included in the migration using implicit selection. A premigration process identifies the relationship between hosts and presented volumes and selects all additional objects to completely migrate the hosts. Consequently, the objects that will be migrated are the combination of the explicit and the implicit selection and may lead to the migration of a large amount of volumes.

For example, selecting a single host results in migration of the following:

•The host as well as any volumes presented to it

•Any other hosts to which those volumes are presented

•Any volumes presented to those other hosts

IMPORTANT: The implicit selection of objects for migration occurs automatically and cannot be modified. If the number of objects selected for migration becomes too large, migration might be canceled before it is started. Once migration begins, it cannot be stopped. See “Aborting a Migration” (page 55).

The maximum number of volumes that can be migrated with MDM or an online migration is 255. If you have more offline volumes to migrate, rerun the migration steps for the additional volumes.

Types of Data Migration