Question:

I'm a new Oracle DBA and after reading several manuals it's still not
obvious that no matter what rollback extent size I choose the max extents is
always 121. Why is this? I thought the max extents would change with the
size I choose i.e. that this would be a denomination of the total rollback
tablespace size.

Answer 1:

If you are runing an Oracle 7.x database with a 2K block size, the
maximum number of extents you can have in any tablespace is 121.

Answer 2:

Prior to Oracle 7.3.4 the maximum number of extents was limited by the block
size.
Every Oracle object has a header block which contains information about the
extents in the object.
In Oracle 7.3.4 it is possible to set maxextents unlimited. This is a
procedure I don't use because I want to exercise control over what is
happening.

Hth,

Sybrand Bakker, Oracle DBA