Defragmentation programs can cause performance problems in ClearSCADA.
To offset this, consider setting the defragmenter to exclude folders where the following database files are located:
- ClearSCADAConfig*.dat
- ClearSCADAData*.dat
- ClearSCADAMetadata.xml
However, you should not exclude historic folders from defragmentation, because these files grow incrementally and can become heavily fragmented. It is desirable to read them as fast as possible for data or journal queries (read performance is improved if files are contiguous). For related information see Anti-virus Scan Exclusions.
Only exclude the directory from the defragmentation program. Do not exclude specific files contained in the directory, because ClearSCADA initially writes the files with random temporary names).
Excluding these directories should not cause any of the following performance problems:
- A new version of the file being created every minute, after which it is never written to again.
- The speed of writing a new version is not related to how fragmented the previous one is (the writing speed will be slower if there is fragmentation of free space though).
- The file only being read on start up of DBServer.