Log Volume 

A database instance has volumes, in which the log writer records all changes to the database contents. These volumes are called log volumes. All log volumes form the log area.

 

Managing Log Volumes

You can configure one or more log volumes when you install a new database instance.

During database operation, you can add new log volumes. The number of log volumes is limited by the database parameter MAXLOGVOLUMES.

See:
Database Manager GUI: SAP DB 7.4, Section Managing Database Instances
Database Manager CLI: SAP DB 7.4, Section Adding a Volume

Log Settings

The log entries are needed to ensure that the database content can be restored if a media device fails. Choose log settings that guarantee secure operation of your database: mirror the log area, only overwrite the log area after the log backup, always leave redo log management activated.

Log Backups

So that you database operates securely, choose log settings that specify that log entries are made (mirrored, if possible), and that log backups are required.

·        To ensure uninterrupted database operation, you must ensure that there is always enough space available in the log area.

·        For safe database operation, it is necessary for the log entries to be backed up at regular intervals (even when you mirror the log area).

Perform log backups at regular intervals. You can best ensure uninterrupted database operation by activating automatic log backups.

The log segment size, the size of the log volume, and the capacity of the backup medium must be matched to each other. The log segment size should be selected so that enough space remains in the log area for any changes made during the backup of a log segment.