Log Volume is full (log mode = legacy) and the database doesn't accept any new requests.

The logvolume is full and the database doesn't accept any new requests.

If the log_mode is set to legacy the logvolume keeps all log segments since the last full backup in the logvolume. If no backups are performed the logvolume can run out of space.

1. Stop the database:
HDB stop

2. Change into the folder mnt00001 of the logvolume (Default: /usr/sap/<SID>/global/hdb/log):
cd /usr/sap/<SID>/global/hdb/log/mnt00001

3. You have to move one of the logvolumes temporarily to another volume where enough space is available. You should free at least 2 GB of space to ensure that the database has enough space to start. To find out the space consumption of each volume execute:
du -sh *

4. Move a volume which consumes at least 2 GB of space (e.g. hdb00003) to a volume with enough free space, e.g. to the data volume (Default: /usr/sap/<SID>/global/hdb/data):
mv hdb00003 /usr/sap/<SID>/global/hdb/data

5. Create a symbolic link to the new folder in the old location:
ln -s /usr/sap/<SID>/global/hdb/data/hdb00003 /usr/sap/<SID>/global/hdb/log/mnt00001/hdb00003

6. Start the database (HDB start) and set the log_mode to 'overwrite' using the following SQL-Statement:
ALTER SYSTEM ALTER CONFIGURATION ('global.ini', 'SYSTEM') SET ('persistence', 'log_mode') = 'overwrite' WITH RECONFIGURE;

7. Restart the database (HDB restart) and use the following SQL-Statement to clean up the logvolume:
ALTER SYSTEM RECLAIM LOG;

8. Set back the log_mode to 'legacy' (you should consider switching to log_mode = normal; see note 1645183 for more information):
ALTER SYSTEM ALTER CONFIGURATION ('global.ini', 'SYSTEM') SET ('persistence', 'log_mode') = 'legacy' WITH RECONFIGURE;

9. Stop the database again and remove the symbolic link:
rm -f /usr/sap/<SID>/global/hdb/log/mnt00001/hdb00003

10. Move the log volume back to its original location:
mv /usr/sap/<SID>/global/hdb/data/hdb00003 /usr/sap/<SID>/global/hdb/log/mnt00001

11. Start the database and perform a backup.