Log files can provide a wealth of information for troubleshooting or planning. Whereas charting, setting alerts, and creating reports on current activity provide instant feedback, working with log files enables you to track counters over a long period of time, allowing you examine information more thoroughly, and document system behavior.
The method of analyzing data is the same, whether the source is current activity or a log file. You can still chart, report and set alerts on data. In addition, you can relog the data at the same or at a shorter interval to compress it, and you can use the Time Window to view a selected portion of the logged data.
You can append and relog log files in several ways:
When you log current activity to an existing log file, the new data is just added to the end of the file. This lets you create a single archive file composed of multiple logs.
However, when you relog data, you can choose a new rate at which the data is collected and averaged. For example, if you collected data at a one-minute interval and relogged it at a five-minute interval, every fifth data point is collected, and the others are discarded. All minimum, maximums, and averages reflect the remaining data only and the new logfile uses only 1/5 of the disk space of the original file.
Note
Data in a log must be in chronological order. If you are relogging to combine existing log files, be sure to relog them in chronological order.
To enable the Relog File button, enter a filename and select at least one counter to log. For specific instructions on how to relog an input log file, see the "Relogging Input Log Files" topic in Performance Monitor Help.