Checklist for server recovery log disks

The recovery log for the server consists of the active log, the archive log, and optional logs for mirroring and failover. Use the checklist to verify that disk systems that are being used for the logs have the characteristics and configuration that are key to good performance.

Question	Tasks, characteristics, options, or settings	More information
Are the active log and archive log stored on disks or LUNs that are separate from what is used for the database and storage pool volumes?	Ensure that the disks where you place the active log are not used for other server or system purposes. Do not place the active log on disks that contain the server database, the archive log, or system files such as page or swap space.	Separation of the server database, active log, and archive log helps to reduce contention for the same resources by different operations that must run at the same time.
Are the logs on disks that have nonvolatile write cache?	Nonvolatile write cache allows data to be written to the logs as fast as possible. Faster write operations for the logs can improve performance for server operations.
Did you set the logs to a size that adequately supports the workload?	If you are not sure about the workload, use the largest size that you can. Active log The maximum size is 512 GB, set with the ACTIVELOGSIZE server option. Ensure that there is at least 8 GB of free space on the active log file system after the fixed size active logs are created. Archive log The size of the archive log is limited by the size of the file system on which it is located, and not by a server option. Make the archive log at least as large as the active log.	For log sizing details, see the recovery log information in technote 1421060. For information about sizing when you use data deduplication, see Checklist for data deduplication.
Did you define an archive failover log? Did you place this log on a disk that is separate from the archive log?	The archive failover log is for emergency use by the server when the archive log becomes full. Slower disks can be used for the archive failover log.	Use the ARCHFAILOVERLOGDIRECTORY server option to specify the location of the archive failover log. Monitor the usage of the directory for the archive failover log. If the archive failover log must be used by the server, the space for the archive log might not be large enough.
If you are mirroring the active log, are you using only one type of mirroring?	You can mirror the log by using one of the following methods. Use only one type of mirroring for the log. Use the MIRRORLOGDIRECTORY option that is available for the IBM Spectrum Protect server to specify a mirror location. Use software mirroring, such as Logical Volume Manager (LVM) on AIX®. Use mirroring in the disk system hardware.	If you mirror the active log, ensure that the disks for both the active log and the mirror copy have equal speed and reliability. For more information, see Configuring the recovery log.