The Sysstat Suite Of Resource Monitoring Tools - Red Hat ENTERPRISE LINUX 4 - INTRODUCTION TO SYSTEM ADMINISTRATION Administration Manual

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2.5.4. The Sysstat Suite of Resource Monitoring Tools

While the previous tools may be helpful for gaining more insight into system performance over very
short time frames, they are of little use beyond providing a snapshot of system resource utilization. In
addition, there are aspects of system performance that cannot be easily monitored using such simplistic
tools.
Therefore, a more sophisticated tool is necessary. Sysstat is such a tool.
Sysstat contains the following tools related to collecting I/O and CPU statistics:
iostat
Displays an overview of CPU utilization, along with I/O statistics for one or more disk drives.
mpstat
Displays more in-depth CPU statistics.
Sysstat also contains tools that collect system resource utilization data and create daily reports based
on that data. These tools are:
sadc
Known as the system activity data collector,
tion and writes it to a file.
sar
Producing reports from the files created by
written to a file for more intensive analysis.
The following sections explore each of these tools in more detail.
2.5.4.1. The
iostat
The command at its most basic provides an overview of CPU and disk I/O statistics:
iostat
Linux 2.4.20-1.1931.2.231.2.10.ent (pigdog.example.com)
avg-cpu: %user
6.11
Device:
dev3-0
Below the first line (which contains the system's kernel version and hostname, along with the current
date), displays an overview of the system's average CPU utilization since the last reboot. The
iostat
CPU utilization report includes the following percentages:
Percentage of time spent in user mode (running applications, etc.)
•
Percentage of time spent in user mode (for processes that have altered their scheduling priority
•
using )
nice(2)
Percentage of time spent in kernel mode
•
Percentage of time spent idle
•
Below the CPU utilization report is the device utilization report. This report contains one line for each
active disk device on the system and includes the following information:
command
%nice %sys %idle
2.56 2.15 89.18
tps Blk_read/s
1.68 15.69
Chapter 2. Resource Monitoring
collects system resource utilization informa-
sadc
, reports can be generated interactively or
sadc sar
Blk_wrtn/s Blk_read
22.42 31175836
07/11/2003
Blk_wrtn
44543290