IBM DS8880 Series, Introduction And Planning Manual

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Consider creating any new fixed block (FB) volumes with T10 DIF protection. This
protection can be used on volumes to which data is migrated, even if the current
host server volumes are not T10-protected. T10 DIF-protected volumes can be used
even if the host server does not currently support T10 DIF.
Selecting a data migration method
The data migration method that you select must provide the best compromise
between efficiency and impact on the system users. The selected method provides
a simple but robust method that minimizes user impact.
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, and typically
requires that updates or changes cease while the movement occurs. Depending on
the amount of data that you are moving and your migration method, data might
be unavailable for an extended period, perhaps several hours. The following
factors might contribute to the migration time:
v Creating new logical volumes or file systems
v Modifying configuration files
v Receiving integrity checks
Consider the following items to determine the best method for your data
migration:
v Management software provides simple robust methods that you can use during
production without disturbing users.
v 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 that is called
Solstice, which is available for the Solaris systems.
– Linux systems also use the LVM.
v Methods that use backup and restore procedures have the most impact on the
system usage. These procedures require that databases and file systems are in
quiescent states to ensure a valid snapshot of the data.
Table 91 compares data migration options and lists advantages and disadvantages
of each.
Table 91. Comparison of data migration options
Type Example Advantages Disadvantages
OS / LVM
Mirroring Logical Volume
Managers, (LVM) Veritas
Volume Manager
(VxVM), Windows Disk
Administrator Little or no
application service
disruption Potential application
delays
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DS8880 Introduction and Planning Guide