Migrating data to a DS8000 storage unit using volume
management methods
The UNIX volume manager method for migrating data is very similar to the
method that is used by AIX systems. It involves the use of commands or a
combination of commands that copy and move the data.
The following methods are available for the UNIX volume manager. The method
you choose depends on your operating environment.
The cplv method
Use the cplv command to make entire copies of logical volumes. You can issue
the cplv command without disrupting access to data that is contained within
the logical volume that it is copying. However, there is one drawback to using
this command. Active logical volumes might not be copied when you use this
command. You must ensure that your logical volumes are closed before you
run this command.
To ensure consistency and limit the problems that are associated with this
command, proceed with the following process:
1. Close your logical volumes either by unmounting the file system where
they are built on, or by shutting down any database that has an open raw
logical volume.
2. Run the cplv command.
3. Update the system configuration file, /etc/filesystems, to include the relevant
configuration data on the new logical volume and file system.
4. Issue the fsck command to run the file system integrity checker to ensure
data consistency within the new logical volumes.
The
migratepv method
This is an ideal method for moving data without disrupting users. Use the
migratepv command to create a mirror of each logical volume that is contained
within the physical volume. Issuing this command also synchronizes both
copies. The benefit of this command is that you can run it on an active system.
You might notice some performance degradation due to the automatic nature
of the creation and the synchronization of the copy. This process writes each
physical partition and locks it from access by any other process. This can slow
down access to the data, but it ensures data integrity.
The mklvcopy, splitlvcopy method
This method is ideal for creating a copy of logical volumes. Use the mklvcopy
command to ensure data integrity by creating a mirror copy of the data and
synchronizing it automatically. Do not run the splitlvcopy command or the
cplv command on an active logical volume. If processes are updating the data
while the split is taking place, the consistency of the data on both copies
cannot be guaranteed. After you run the splitlvcopy command, update the
system configuration files. Include the relevant configuration data regarding
the new logical volume and file system. Then issue the fsck to run the file
system integrity checker to ensure data consistency within the new logical
volume.
The mklvcopy, rmlvcopy method
This method is ideal for migrating active logical volumes when a slight
performance loss is acceptable. This method creates and removes mirrors
automatically, ensuring data integrity.
150 DS8000 User’s Guide
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