Consider Separate Disks for Critical Data Components

If you place the root dbspace, logical log, and physical log in separate dbspaces on separate disks, you can obtain some distinct performance advantages. The disks that you use for each critical data component should be on separate controllers. This approach has the following advantages:

• Isolates logging activity from database I/O and allows physical-log I/O requests to be serviced in parallel with logical-log I/O requests
• Reduces the time that you need to recover from a failure

  However, unless the disks are mirrored, there is an increased risk that a disk that contains critical data might be affected in the event of a failure, which will bring the database server to a halt and require the complete restoration of all data from a level-0 backup.

• Allows for a relatively small root dbspace that contains only reserved pages, the database partition, and the sysmaster database

  In many cases, 10,000 kilobytes is sufficient.

The database server uses different methods to configure various portions of critical data. To assign an appropriate dbspace for the root dbspace and physical log, set the appropriate database server configuration parameters. To assign the logical-log files to an appropriate dbspace, use the onparams utility.

For more information on the configuration parameters that affect each portion of critical data, see Configuration Parameters That Affect Critical Data.