HP EVA to 3PAR StoreServ Online Import Migration Guide (T5494-96571, January 2013)

5. The 3PAR storage system begins copying data from the EVA to local storage on the 3PAR
storage system. No writes of new data will be made to the 3PAR storage system or the EVA
while the host is shutdown. Data from the EVA is written to the 3PAR once the import process
begins.
6. Once the 3PAR has started copying the data the host is zoned to the destination 3PAR array
and brought back up. The host is now accessing its data via the destination 3PAR while the
migration of data from the EVA continues.
7. The 3PAR continues to mirror writes to the EVA, so the EVA retains a consistent copy of the
data on the volumes being migrated.
8. Once the 3PAR storage system has copied all the data on a volume to local storage, it stops
mirroring writes to the EVA for that volume. The volume is now a normal local volume on the
3PAR storage system.
9. When all of the host volumes have been copied to the 3PAR storage system, the migration is
complete. The exports from the EVA to the 3PAR storage system and the host can now be
removed.
10. If no additional migrations are to be performed, the zoning between the source EVA and the
destination 3PAR storage system can now be removed.
Types of data migration
HP EVA to 3PAR StoreServ Online Import supports three types of data migration. The appropriate
type of data migration is selected automatically based on the objects being migrated.
• Online—Selected when migrating a non-Windows host or a virtual disk presented to a
non-Windows host. During online migration, all presentation relationships between hosts and
virtual disks being migrated are maintained. Host I/O to the data is not disrupted during an
online migration.
• Offline—Selected when migrating one or more unpresented virtual disks. During offline
migration, only the selected virtual disks are migrated. No hosts are migrated in this situation.
• Minimally disruptive—Selected when migrating a Windows host or a virtual disk presented
to a Windows host. The host DSM used to access the storage system must be reconfigured
from the EVA DSM to a DSM that will communicate with the destination 3PAR storage system.
Host I/O is interrupted only during the time it takes to reconfigure the host. For more
information, see “Reconfiguring the Windows host DSM” (page 10)
Understanding what data is migrated
Data migration can be done by selecting a host or a virtual disk on the source EVA. In addition
to the host or virtual disk explicitly selected for migration, other objects may be included in the
migration using implicit selection. A pre-migration process identifies the relationship between hosts
and presented virtual disks and selects all necessary objects to completely migrate the hosts.
Consequently, the explicit selection can lead to many implicit selections and a large amount of
data being migrated. For example, selecting a single host will result in migration of the host, any
virtual disks presented to it, any hosts to which those virtual disks are presented, and any virtual
disks presented to those hosts.
IMPORTANT: The implicit selection of objects for migration is done automatically and cannot be
modified. If the number of objects selected for migration becomes too large, the migration can be
canceled before it is started. Once a migration begins, it cannot be stopped.
The migration process selects objects to migrate using the following rules:
• Host—When selecting a single host or group of hosts with virtual disk presentations, all the
virtual disks presented to the host(s) are migrated. In addition, any presentations the source
6 Overview of HP EVA to 3PAR StoreServ Online Import