# Log File -- Advanced Concepts

Below are a few advanced concepts that will help you understand how the log file is managed:

- Disabling the log file will not delete its contents.
- Log Files are confined to the log file reserve space.
- Any fully delivered log file segment can be automatically over-written at any time. These segments are preserved as long as possible.
- The treatment of undelivered log file segments is determined by the "when reserved storage is completely full" parameter.
- When no destinations exist for log file downloads, or when overwrites of undelivered data are enabled, every segment is considered as fully delivered.
- You cannot set the log file reserve space to a value that will leave less than 1K bytes of memory available for speech-database files. Operator must manually free up some extra memory space.
- You can set the log file reserve to a value smaller than that currently occupied by the existing log file data. The "when reserved storage is completely full" parameter controls what happens to the existing data. The operator may need to clear out the log files to regain space for speech and/or database.
- The maximum size for log file reserve depends on NVRAM usage at the time.
- The log file reserve parameter is read-only while working OFFLINE.
- Any log file segment skipped (because of filtering parameters) during any successful reporting session will be marked as delivered to that destination. For example, suppose you have log file segments going back to yesterday and now deliver a report containing only data from the last hour. All segments from yesterday will be marked as delivered to that destination, even though they actually were skipped.

Things to Remember about Log Files:

1. Newly disabled channels will not get rendered, even if not disabled at time the data sampling occurred.
2. Destination/Channel links will not get rendered.
3. Altering channel or destination messages from before the change to appear incorrect. (Messages only, data values not impacted)