Re: RAC and undo tablespace

wagen wrote:

>Why are separate UNDO tablespaces required for each instance in a RAC
>cluster?

Not knowing anything about it, I'll throw out some guesses anyways, least to most likely:

Instance crash & recovery: So you don't affect the other instances multiversioning.

Performance & Scalability: some OLTP db's do more i/o to undo than any other TS.

Different tuning for instances: OLTP on one and DW on other could have quite different requirements for undo.

Inter-instance communication: reduce having to get data from other instance in general for read consistency. RAC shares database files, but each instance has to handle the buffering of that data. There's generally enough talk going on just to resolve who owns what anyways, you probably don't want to add undo to that too.

jg

--
@home.com is bogus.
http://orcasthoughts.blogspot.com/2005/07/new-oracle-packaged-mini-triggers-with.html