Transaction (and Backup) Log Location Guidelines
You can optionally configure a backup transaction log file for use. The online system will write identical transactions to both copies. This dual logging can limit performance during heavy log writing. Volume mirroring is faster, but loss of both sides of the mirror has been known.
Consider the following when choosing the locations for the transaction or backup transaction log file:
• Do not locate the primary and backup transaction log files on the same disk.
• If possible, avoid installing the primary or backup transaction log files on the same disk as your data location because long (5 minutes or longer) peaks in writing activity will stress both the data and transaction log file writing bandwidth.
• Put the transaction log file on separate disks from your checkpoint, dump, and journal files so that you can perform offline recovery of databases if the transaction log file disk fails.
Note: On Ingres for Linux, the backup transaction log is disabled by default. To enable the backup transaction log, set the environment variable II_DUAL_LOG to the location of the backup log file (either in the response file or prior to installing).
Note: On UNIX (but not Linux) the transaction log file can be located on a raw partition to increase writing bandwidth. Bypassing the file system also eliminates the small possibility of loss through file system failure.