Monitoring the SAP Log Disk

The size of the transaction log must be checked regularly to work out how much free space is available on the log disk. There should always be enough free space to allow the next file extension. When the SAPsystem has been installed the autogrow increment is set. At least the size of this increment should be available on the log disk to permit the next file extension. If less space is available and the transaction log file fills up, the SAP system comes to a standstill.

Ideally, the transaction log should never be filled to more than 60-70%. If the transaction log regularly exceeds this level between 2 transaction log backups, the transaction log must be saved at more frequent time intervals.

The size of the log can be assessed on the basis of information given for completed backups in the SAP transaction for Backup and Restore Information.

Procedure

1. Access the DBA Cockpit with transaction DBACOCKPIT.
2. Choose Backup and Recovery → Backup History.
3. Select Log Backups.

   A result list appears.

4. For the last 30 days, select each row and then History info to find out the number of pages that were processed during the backup. To work out the amount of space used in the transaction log, multiply the number of Backup Page Count for the SAP database log by 8 KB. You can then work out how much free space is left on the transaction log disk.
   Note

   If you use a RAID1 disk system exclusively for the SAPtransaction log and create hourly log backups, you rarely encounter space problems. The SAP log file is initially created with a size of 1 GB. The smallest disk normally has 9 GB space and the log file can therefore grow to 9 GB.