Unable to Extend Rollback Segment

[pando]

I dont understand your question, are you asking how to size or you mean why you hit the error....?

[ronnie]

Now I know why I hit the error... Thanks for the help.

The question was about basics in sizing Rollback segments and things to keep in mind.

[tamilselvan]

Sizing RBS is an iterative process.

Query from v$rollstat when the db has high volume of transactions.
The aveactive column value will be the starting size (for initial and next) for the RBS.