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Entry type: FAQ Entry ID: 34473263, Entry date: 12/06/2017

How many single segments can be connected to the SQL server in PCS 7 without impairing performance?

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For archive configuration you should make sure that the sum of all the single segments (Tag Logging Fast, Tag Logging Slow and Alarm Logging) does not exceed a certain number.

Configuration Notes
A maximum of 200 single elements connected to the SQL server has proven to be a practical number. You should not exceed this number greatly, because too many single segments attached can lead to performance problems of the Microsoft SQL server. This in turn can lead to data management problems.

A single segment should not exceed the size on the server or the central archive server (CAS) as given in Table 01.

Product version Segment size on server Segment size on CAS
up to PCS 7 V7.1 (up to WinCC V7.0) 700 MB 1 GB
PCS 7 V8.0 SP1+SP2 and higher (WinCC V7.0 SP3 and higher) 2 GB 2 GB
PCS 7 V8.1 and higher 2 GB  -
Table 01

With SIMATIC PCS 7 V8.1 and higher the CAS is no longer supported. Alternatively you have long-term archiving with SIMATIC PCS 7 Process Historian (PH). More information about the PH in the manual
"Process Control System PCS 7 Operator Station (V8.1)", section 11.10
"Configuration and Utilization of a Process Historian".

Rule for the central archive server "CAS":
On the central archive server you make the size of the single segments significantly greater than the size of the single segments on the OS server.

Further Information

Additional Keywords
Database segments, Archive segments, Database performance


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