Sysstat

Sysstat is a collection of performance monitoring utilities for Linux and other Unix-like systems. It provides tools for collecting, reporting, and logging system activity data to help analyze system performance and troubleshoot issues. The package typically includes sar, iostat, mpstat, pidstat, and sadf. These tools can generate reports from stored data or capture current statistics, and they can produce output in human-readable form or in machine-friendly formats.

Data collection and reporting are the core functions of sysstat. On systems that enable it, a data collection daemon or cron/timer-based job records statistics at regular intervals and stores them in binary files, typically under /var/log/sysstat. The sar utility can read these files to create historical reports. Sadf can extract data from the binary archive or convert it to different formats for further analysis, such as CSV or interactive text reports. The other tools provide targeted views: iostat focuses on input/output statistics, mpstat on per-processor usage, pidstat on per-process activity, and sar on system-wide activity as a whole.

Usage commonly involves reading historical data or collecting current statistics. Examples include using sar -u to display CPU usage, iostat -xz for device and CPU I/O statistics, mpstat -P ALL to summarize per-processor activity, and pidstat to monitor specific processes. Sadf can export data for external tools. Sysstat is widely available in Linux distributions and is typically licensed under the GNU General Public License. It is a valuable resource for performance analysis, capacity planning, and troubleshooting in both server and desktop environments.