Disk Buffering

CAUTION: The buffer file path must be either proj_dir/db/wincc_oa/nga or a directory outside of proj_dir/db/wincc_oa. Otherwise inconsistencies during the redundancy synchronization could occur.

Note: NGA delays the query of statistical functions until all necessary data present in buffer files is written to the database.

Figure 1. Buffer Files Location and File Prefix

Read Buffer Blocks after restart: This setting indicates if at startup of the NGA existing buffer files (from the last session) should be processed or not.
Buffer files location: Directory for saving disk buffers. Default location (when empty) is <projdir>/db/wincc_oa/nga. Absolute and relative (to <projdir>/db/wincc_oa) paths can be specified.
Buffer Files Prefix: As buffer file names are just numbers which increase over time, each backend has to have a specific prefix when storing all buffers in the same directory to avoid identical filenames across backends.