Your system administrator selects the data migration method
that is the best compromise between efficiency and impact on the users of
the system.
Most methods of
data migration affect the everyday operation of a computer system. When data
is moved, the data must be in a certain state, typically requiring that updates
or changes cease while the movement occurs. Depending on the amount of data
that you are moving and your migrating method, data could be unavailable for
an extended period of time, perhaps several hours. The following factors might
contribute to the migration time:
- Creating new logical volumes or file systems
- Modifying configuration files
- Receiving integrity checks
The following items are more than likely among the topics considered by
your system administrator to determine the best method to use to migrate your
data:
- Management software provides simple robust methods that you can generally
use during production without disturbing users.
- The AIX® logical
volume manager (LVM) provides methods that you can use at any time without
disrupting user access to the data. You might notice a small performance degradation,
but this is preferable to shutting down databases or requiring users to log
off the system.
Notes: - AIX and
HP-UX 11.xx ship with logical volume management (LVM) software as part
of the base operating system. LVM provides complete control over all disks
and file systems that exist on an AIX system. HP-UX has similar volume management
software.
- Sun Microsystems has a basic volume management product called Solstice,
which is available for the Solaris systems.
- Methods that use backup and restore procedures generally have the most
impact on the system usage. They require that databases and file systems be
in quiescent states to ensure a valid snapshot of the data.