sar, iostat and mpstat - system performance tools for Linux The sysstat package contains the sar, mpstat, iostat sadf and sa tools for Linux. The sar command collects and reports system activity information. The iostat command reports CPU utilization and I/O statistics for disks. The mpstat command reports global and per-processor statistics. The sadf command is used to display data collected by sar in various formats. The statistics reported by sar concern I/O transfer rates, paging activity, process-related activities, interrupts, network activity, memory and swap space utilization, CPU utilization, kernel activities and TTY statistics, among others. Both UP and SMP machines are fully supported.