Data migration on IBM FAStT
I have an IBM FAStT and just recently added an expansion tray. Now, the original FAStT has 73 GB drives and the new expansion tray has 146 GB drives, so if I try to expand an array using the 146 GB drives I lose space on that array due to RAID. I want to move an array completely to all 146 GB drives. What is the best way to do this?
The process of migrating data can be one of the most cumbersome processes due to a number of issues that may arise. Your specific question is based on moving data within a single storage system with dissimilar drive types. One approach is to use software that will provide this ability that not only moves the data, but expands the volume size. For SAN
-based storage there is TDMF Open by SoftTek. This is host-based software that can be used to migrate data from one set of storage to another -– whether it is internal within the array
or external to another storage system. Customers can also use Veritas Volume Replicator, Legato Replistor, NSI DoubleTake and XOSoft.
Another approach is actually very widely used, which is backing up the data using your backup software and then restoring it to the new storage. This can be a slow process and you may want to consider backing up to disk instead of a tape library if there is a great deal of data. The problem with this approach is that new data being generated will not be a part of that restored data set. This issue can be minimized if you are using backup software that supports synthetic full backups (i.e. CommVault, Legato and TSM).
Additionally, most storage vendors provide a data mover service to perform this task for you. In some cases, this makes a great deal of sense, especially if you can negotiate it as part of acquiring that vendor's products. However, if you are not in a position to negotiate, you may have to pay for this service.
This was first published in May 2005