User Guide

Backup
16
History Database
391
Siemens User Guide Version 2.1
A6V10415471_en_a_21
Building Technologies 2015-07-15
16.2.3 Automatically Deleting Data Entries
By enabling the Delete Log Entries function, old historical information can be
automatically deleted from the history database (for details, see
System
Management Console
A6V10415491). History data deletion can be specified for
each individual data group.
NOTICE
Deleting
Historical data permanently deletes it; the historial data cannot be restored.
Define automatic data backup (see Automating Data Backup [➙ 390]) to be
carried out prior to deletion.
 You want to permanently delete unneeded data entries from the history
database.
1. In System Browser, select Management View.
2. Select Project > Management System > Servers > Main Server > History
Database > Archive Groups > [Data group].
3. Click the Operation tab.
– Minimal retention span defines the minimum length of the time period and
Max retention span unit defines the associated unit.
– Minimal retention count defines how many entries still exist in the History
Database after each deletion (see document
System Management Console
A6V10415491). Type 0 if you do not want to limit the entries.
4. Click the Extended Operation tab.
 The properties for the corresponding data group display.
5. Type the following data and confirm with Set:
– Delete schedule start defines the first time to delete data.