Overview Of Hp 3Par-To-3Par Storage Peer Motion; About Peer Motion; How Peer Motion Works; Migration Types - HP 3PAR StoreServ 7200 2-node Manual

1 Overview of HP 3PAR-to-3PAR Storage Peer Motion

About Peer Motion

HP 3PAR Peer Motion controls the migration of a host and its data from a source system to a
destination system with as little disruption to the host as possible. With Peer Motion, you can copy
the virtual volumes and system configuration information to a new system with no changes to host
configurations, no loss of access by a host to its data in an online migration, and only a minimal
outage during a minimally disruptive migration.
Peer Motion runs on a Windows or Linux host that is connected to the destination system. The
destination system non-disruptively moves the volumes from the source system while servicing I/O
requests from the hosts. After the data migration is complete, the source system can be disconnected
from the hosts and repurposed.
At the start of the process the host is connected to the source; at the end, the destination.
NOTE: Peer Motion is supported when the destination system is running HP 3PAR OS 3.1.2 or
a later version. If you are running HP 3PAR OS 3.1.1, refer to the HP 3PAR Peer Motion Manager
1.1.0 Software User's Guide.

How Peer Motion Works

At first, the host (Host1) is connected (zoned) only to the source array (Source1), where its volumes
reside.
A new array, the destination (Dest1), is connected (zoned) to the source array. This destination is
configured as another host on the source array, and all of the volumes that are exported to Host1
are also exported to Dest1.
Dest1 admits these volumes, which creates a set of peer volumes on Dest1 that are fully backed
by the data on Source1. Host1 is also connected to (defined on) Dest1. At this point, the admitted
volumes on Dest1 can be exported to Host1.
Host1 performs the appropriate SCSI rescan/multipathing reconfiguration to pick up the exports
from Dest1, which Host1 sees as additional paths to the volumes that it already recognizes.
After Host1 recognizes the paths from Dest1, its connection (zoning) to Source1 can be removed.
Host1 retains access to all its data via the connection to Dest1.
At this point, Dest1 is the only path to the data for Host1. Dest1 begins the process of copying the
data from Source1 to local storage on Dest1. During this process, Dest1 continues to mirror writes
to Source1, so Source1 retains a consistent copy of the data on the volumes that are being migrated.
Once Dest1 has completely copied the data on a volume to local storage, it stops mirroring writes
to Source1 for that volume, and the volume becomes a normal local volume on Dest2.
When all of the volumes for Host1 have been copied to Dest1, the migration is complete. The
exports from Source1 to Dest1 and Host1 can be removed, and Host1 now uses only Dest1 for
access to the volumes. Source1 is no longer required for those volumes.
At this point, the user can move on to migrating another host, or if there are no more migrations
outstanding, can remove the zoning between Source1 and Dest1 and clean up the host definition
of Dest1 on Source1.

Migration Types

There are three types of data migration:
Online — With online migration, the volumes copied from the source system remain available
to the hosts throughout the process and are exported to the hosts with no interruption to the
About Peer Motion 5