User Guide

16
Backup
History Database
392
Siemens User Guide Version 2.1 A6V10415471_en_a_21
Building Technologies 2015-07-15
– Delete schedule period defines the length of the time interval and Delete
schedule period units defines the associated unit.
NOTE: The greater the interval, the more data is saved during the
maximum time span.
– Maximal retention span defines the maximum length of the time period and
Max retention span unit defines the associated unit.
– Maximal retention count defines how many entries still exist in the History
Database after each deletion (see document
System Management Console
A6V10415491). The default value of 999,999,999 applies if you do not want
to limit the entries.
6. Click Enable to enable the process.
 Deletion is defined for the applicable data group and starts as per the defined
date and time setting.
Setting Examples for Storage by Days
Max retention time of data
in the HDB
Min.retention
span
Min.retention
count
Max.retention
span
Max.retention
count
Delete
period
30 days 10 days 0 30 days 999'999’999 1 day
90 days 30 days 0 90 days 999'999’999 1 day
180 days 90 days 0 180 days 999'999’999 1 week
Setting Examples for Storage by Number of Entries
Database
Min.retention
span
Min.retention
count
Max.retention
span
Max.retention
count
Delete
period
SQL Server Express 1 sec 1’000’000 99 years 23’000’000 1 day
SQL Server 1 sec 10’000’000 99 years 350’000’000 1 day
For more information on calculating the database size and time span, see Values
and Data Capacity Settings [➙ 394].
NOTE:
No additional historical data is deleted if deletion is disabled with Disable .
2a. The start date is in the past: When re-enabling with
Enable , the historical data
outside the defined time period is immediately deleted.
2b. The start date is once again set to the future: When reenabled with
Enable ,
deletion starts as per the defined data and time setting.
16.2.4 Checking the Database Size
1. In System Browser, select Management View.
2. Select Project > Management System > Servers > Main Server > History
Database > Tables.
3. Click the Extended Operation tab.
 The data size properties display.
Database size Displays the amount of storage used for the entire
database in MB.
Log size Displays the storage used for the applicable data