Donald K. Burleson
* The SYSTEM tablespace, if you split
out the tool tables, should only require 300 to 400 MB of disk
space, this has increased dramatically due to increased Java and
other stored procedures in the Oracle system.
* The TOOLS tablespace will depend entirely on the amount of
development you expect. At one site with 16 applications being
developed, nearly 90 MB were required for the TOOLS tables.
* The ROLLBACK tablespace will again be driven by the number and
size of rollback segments you require. The number and size of
rollback segments is driven by the number of transactions per
rollback segment, the number of users, and the maximum size of
nonbatch transactions. With Oracle8i and Oracle, you can create a
large rollback segment and leave it offline until it is needed for a
large transaction, and then use the SET TRANSACTION USE ROLLBACK
SEGMENT command to utilize it after bringing it online. The number
of rollback segments is driven by the number of expected
transactions and can be estimated by the equation:
NUMBER OF DML TRANSACTIONS / TRANSACTIONS PER ROLLBACK SEGMENT
* The number of transactions will be driven by the number of users
and types of database operations they will be doing. In fact, if the
Oracle kernel sees a violation of the above formula, it will bring
online any available public rollback segments. In Oracle you
should also consider if you wish to use the UNDO tablespace, which
takes the place of the rollback segments if it is configured. By
default Oracle sizes the UNDOTBS at 200 megabytes.
This is an
excerpt by Mike Ault’s book “Oracle
Administration & Management”. If you want more current Oracle tips
by Mike Ault, check out his new book “Mike
Ault’s Oracle Internals Monitoring & Tuning Scripts” or
Ault’s Oracle Scripts Download.
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