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Thursday, October 8, 2009

ASM Migration Methods

Over the last year, I've been asked to spend some time researching different methods to migrate from filesystem to Automatic Storage Mgmt. We're getting ready to migrate ~300 AIX and SUSE linux databases to ASM, reduced downtime and complexity are key to making the migration a success. From what I've seen, there's no official, universally accepted migration method-probably because there are so many pros/cons to each. Last week I had a meeting with IBM's Oracle expert who mentioned datapump as a migration method! I wouldn't have even considered that...we're talking about petabytes of data. Even though ASM has been around for years, there seems to be some confusion on this topic (even by experts) so I've chosen it to be my first series of posts. The methods we're going to review are:

1. A simple, quasi-MAA option using recovered datafile image copies
2. The non-MAA "in mount mode, rman copy"
3. Oracle's MAA option
4. A variation on Oracle's MAA option using rman active duplicate (to a local standby)

The first one also doubles as a nice backup strategy to reduce MTTR...its now Oracle's recommended backup strategy. I'd love to hear any good alternate methods you've come across...Stay tuned for the details...