Chapter 3. Planning 79
3.17  Data migration from a non-virtualized storage subsystem
Data migration is an important part of a Storwize V7000 implementation. Therefore, you must 
prepare a detailed data migration plan. You might need to migrate your data for one of the 
following reasons:
/SM590000Redistribute workload within a clustered system across back-end storage subsystems
/SM590000Move workload onto newly installed storage
/SM590000Move workload off old or failing storage, ahead of decommissioning it
/SM590000Move workload to rebalance a changed load pattern
/SM590000Migrate data from an older disk subsystem to Storwize V7000-managed storage
/SM590000Migrate data from one disk subsystem to another disk subsystem 
Because multiple data migration methods are available, choose the method that best fits your 
environment, operating system platform, type of data, and the application’s service level 
agreement (SLA).
Data migration methods can be divided into three classes:
/SM590000Based on operating system; for example, using system’s Logical Volume Manager (LVM)
/SM590000Based on specialized data migration software
/SM590000Based on the Storwize V7000 data migration features
With data migration, apply the following guidelines:
/SM590000Choose the data migration method that best fits your operating system platform, type of 
data, and SLA.
/SM590000Choose where you want to place your data after migration in terms of the storage tier, 
pools, and back-end storage.
/SM590000Check whether enough free space is available in the target storage pool.
/SM590000To minimize downtime during the migration, plan ahead of time all of the required 
changes, including zoning, host definition, and volume mappings.
/SM590000Prepare a detailed operation plan so that you do not overlook anything at data migration 
time. Especially for a large or critical data migration, have the plan peer reviewed and 
formally accepted by an appropriate technical design authority within your organization.
/SM590000Perform and verify a backup before you start any data migration. 
/SM590000You might want to use the Storwize V7000 as a data mover to migrate data from a 
non-virtualized storage subsystem to another non-virtualized storage subsystem. In this 
case, you might have to add checks that relate to the specific storage subsystem that you 
want to migrate. 
Be careful when you are using slower disk subsystems for the secondary volumes for 
high-performance primary volumes because the Storwize V7000 cache might not be able 
to buffer all the writes. Flushing cache writes to slower back-end storage might impact 
performance of your hosts.
For more information about data migration using Storwize V7000, see 11.5, “Volume mirroring 
and migration options” on page 512.