Database redo logs

Oracle redo logs record all changes to the data files. The normal redo log setup consists of five groups; each group has two members. These members are split between the two locations, /oralogs1 and /oralogs2.

Five redo log groups are normal for systems that are going to be set up in archive log mode. It is suggested when the system is being backed up.

The size of the redo logs depends on the amount of activity on the system. It is usual for redo log groups that switch once every 20 minutes. The size of the system affects the switching frequency.

For small to medium systems, the redo logs can be set between 400 MB and 1G for each member. It results in 400 MB * 2 members * 5 groups => 4 GB. 4 GB is divided evenly between /oralogs1 and /oralogs2.

For a larger system, the redo logs can be sized at 3 GB each for each member. The results in 3 GB * 2 members * 5 groups => 30 GB. 30 GB is divided evenly between the /oralogs locations.

The configuration and sizing of the database redo logs are updated and delivered to the customer in a customer database template, vtdb_<customer_name>.dbt.

See section Updating customer database template , for information on updating the database redo logs with the correct sizings and locations.