Re: Understanding Rollback Segment Sizes

steven_nospam at Yahoo! Canada wrote:
>
> Thanks much Margaret,
>
> At least I was understanding the older RBS setups right. Essentially
> with the current setup, my maximum RBS size for each was 500MB or 2GB
> total. As you mentioned, if I add more later, I would also need to
> increase the file system size. But this is true of ALL our
> filesystems...We have to increase them whenever we add an additional
> data file for the DATA tablespace.
>
> We are on an AIX 5 system and I believe there is a limitation of 2GB
> file sizes, although we used to also have a limitation on file system
> sizes (eliminated with enhanced file systems - jfs2). I think the
> original plan was to spread the load across multiple disks and put one
> RBS on each spindle, but since we have them all in one FS, we really
> dont have control at that level unless we separate them out.
>
> My thought was to change the three 1GB and one 500MB data files in the
> RBS to use only two 2GB data files, and adjust the maxextents so I
> would make more use of the space that was reserved.
>
> However, I just received word down from management that I can go ahead
> and use the Undo tablespace method as long as I document it, updating
> our install procedures, and we will see how things go with the test
> phase of this install. (Essentially, I will be able to test because the
> migration from 8i to 9i on this new server requires a 2-4 week testing
> phase before the actual LIVE migration.)
>
> Thx to all for the help again.
>
> Steve

Sounds like you are doing everything right!

I've found the pretty pictures in OEM are good for showing to management, so they feel confident that the technical staff is doing good things. It works best if you learn and understand the goings-on behind the scenes. Highly recommend books by Tom Kyte, especially since he relates how things differ from other database engines.

If you run into any problems with undo, don't hesitate to ask here. It's a definite improvement over the old way.

jg

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