Chapter 8. Planning Data Migration - IBM DS8880 Series Introduction And Planning Manual

Chapter 8. Planning data migration

The planning and methods of data migration for the storage system vary by
environment.
When you plan for data migration, consider the following factors:
Note: The following lists do not cover every possibility. They provide a high-level
view of some of the tools and factors that you can consider when you move data.
Data
Operating system
Storage system
Time and complexity
When you replace existing storage, partition the storage so that the virtual disks
are similar in configuration to the disk drives that they are replacing. New
configurations must be large enough to accommodate the existing data.
You might want to take advantage of this opportunity to do some remapping. The
allocation and distribution of data are not required to be a straight one-to-one
relationship, although that is possible. For instance, you can take advantage of
using a maximum of 255 logical subsystems whereas the prior limitation was 32
logical subsystems.
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v How much data is to be migrated?
v Is it a IBM Z or UNIX system? Consider using IBM Remote Mirror and
Copy functions such as Metro Mirror, Global Mirror, or some variation
of a logical volume manager.
v Is it z/OS? Consider using DFDSS, though there are many choices.
v Is it VM? Consider using DASD Dump Restore or PTAPE.
v Is it VSE? Consider using the VSE fastcopy or ditto commands.
Your system administrator selects the data migration method that is the
best compromise between efficiency and impact on the users of the storage
system.
v Are the storage systems involved the same type with the same level of
licensed machine code?
v Are the storage systems different? If the storage systems are different,
ensure that the new configuration is large enough to accommodate the
existing data. You also want to ensure that the virtual disks are similar
in configuration to the disk drives that they are replacing.
v What duration of service outage can be tolerated? Typically data
migration requires that updates or changes cease while the movement
occurs. Also, depending on the amount of data that you are moving and
your migrating method, data might be unavailable for an extended time,
even several hours.
v Does the complexity and time that is involved require the services of
IBM through International Global Services? Contact your technical
support representative for more information.
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