varlogsysstat

Varlogsysstat refers to the /var/log/sysstat directory used by the sysstat performance monitoring utilities on many Unix-like systems. The sysstat package includes tools such as sar, iostat, mpstat, pidstat, and sadf, which collect and report on various aspects of system activity. When enabled, these tools generate historical data files that are stored in this directory for later analysis.

The data in /var/log/sysstat consists of daily statistical files that capture metrics like CPU usage, memory usage, disk I/O, network activity, and process statistics. The primary reporting tool, sar, reads these files to produce summaries and detailed reports on system performance. Other utilities in the suite provide complementary statistics or export data for further analysis. The exact file naming convention can vary by distribution and sysstat version; common patterns include files named saYYMMDD or saDD, containing binary or compact-form data used by sar and related programs.

Data collection is typically configured through the sysstat configuration file, commonly located at /etc/sysstat/sysstat.conf, and is scheduled via a cron job or a systemd timer (for example, a daily sa1 invocation at midnight). Retention and rotation of the files depend on system policy and disk space, with older files often purged or archived according to log rotation settings.

Access to the directory is controlled by file permissions and can generally be read by users with appropriate privileges to run sar or other sysstat tools. The varlogsysstat data provides historical context for performance troubleshooting, capacity planning, and trend analysis, and is a central component of many server monitoring setups.