Regarding Parallelism in RMAN

[sivakumarocp]

Hi Tim,

I am trying to do cross platform migraion from solaris to linux host.
my source db has (125G in size) but got only 2 hrs downtime to migrate to Linux host.
I need to convert two tablespace.(where the customer data resides). during the RMAN tablespace convert process if I am using parallelism 6 or 8 will it speed upthe process ( note : those two tablespaces has 11 datafiles each).

[Tim...]

Hi.

The answer to that is, "it depends".

For any parallel task, things will only work faster in parallel if there are no limiting factors. For example, lets say I am performing a task in a single threaded fashion and I am maxing out my disk I/O (or CPU or memory), then attempting to perform the same operation in parallel will actually slow down the process, since I now have multiple slaves fighting over the same I/O subsystem.

So, assuming you have no limits on your system, using parallel will increase performance, but as soon as you hit a bottleneck, adding more slaves will actually reduce performance.

As with everything, the only way to find out is to run a test.

Cheers

Tim...