Super practical! Sar commands that will make you a Linux master

I. Overview

The sar command presents a system usage report using data collected from system activity. These reports are made up of different sections, each containing the type of data and when the data was collected. The default mode of the sar command displays CPU usage at different time increments for various resources accessing the CPU (such as user, system, I/O scheduler, etc.). Additionally, it displays the percentage of idle CPU for a given time period. The average value for each data point is listed at the bottom of the report. sar reports collected data every 10 minutes by default, but you can use various options to filter and adjust these reports.

Similar to the uptime command, the sar command can also help you monitor the CPU load. sar allows you to understand when excessive load occurs and the specific details that may be causing it. sar provides more detailed data to help you better analyze system performance and deal with potential problems in a timely manner.

The syntax of the sar command is:

# sar [选项]

2. sar command example

1. Install sar command

To install the sar command, you need the "sysstat" package.

# yum install sysstat
# rpm -ivh sysstat-2.3.4

Configure sar to retain logs beyond the default 7 days.

# vi /etc/sysconfig/sysstat

Change the "HISTORY" parameter.

2.CPU usage

Get the current CPU usage.

# sar 2 10
# sar -p 2 10
# sar-P ALL 2 10

To get the CPU usage of the previous date, such as the 14th:

# sar -P ALL -f /var/log/sa/sa14

c. To get the CPU usage from 7am to 3pm on the 10th of the month (that is, at a specified time):

# sar -P ALL -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

3.Memory usage

Get current memory usage:

# sar -r 2 10

To get the memory usage of the previous date, such as the 14th:

# sar -r -f /var/log/sa/sa14

To get the memory usage from 7am to 3pm on the 10th of the month (that is, the specified time):

# sar -r -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

4. Exchange usage

To get current swap usage:

# sar -S 2 10

To get the swap usage of the previous date, such as the 14th:

# sar -S -f /var/log/sa/sa14

To get swap usage from 7am to 3pm on the 10th of the month:

# sar -S -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

5.Load average

To get current load average statistics:

# sar -q 2 10

To get the load average statistics of the previous date, such as the 14th:

# sar -q -f /var/log/sa/sa14

To get load average statistics for the 10th of the month (7am to 3pm):

# sar -q -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

6. Use paging

To get the current paging usage:

# sar -B 2 10

To get the pagination usage of the previous date, such as the 14th:

# sar -B -f /var/log/sa/sa14

To get usage from 7am to 3pm on the 10th of the month:

# sar -B -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

7.IO usage

Get current IO usage:

# sar -B 2 10

To get the IO usage of the previous date, such as the 14th:

# sar -B -f /var/log/sa/sa14

To get IO usage from 7am to 3pm on the 10th of the month:

# sar -B -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

8. Disk IO usage

Get current disk IO usage:

# sar -d -p 2 10

To get the disk IO usage of the previous date, such as the 14th:

# sar -d -p -f /var/log/sa/sa14

To get the disk IO usage from 7am to 3pm on the 10th of the month:

# sar -d -p -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

9.Network statistics

To obtain current network device statistics:

# sar -n DEV 2 10

To obtain the network device statistics of the previous date, such as the 14th:

# sar -n DEV -f /var/log/sa/sa14

To get network device statistics from 7am to 3pm on the 10th of the month:

# sar -n DEV -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

10. Power management statistics

To get current power management usage:

# sar -m 2 10

To get the power management usage of the previous date, such as the 14th day:

# sar -m -f /var/log/sa/sa14

To get power management usage from 7am to 3pm on the 10th of the month:

# sar -m ALL -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

11.Memory Statistics (Page Activity)

To get current memory statistics:

# sar -r 2 10

To get the memory statistics of the previous date, such as the 14th day:

# sar -r -f /var/log/sa/sa14

To get memory statistics for the 10th of this month (7am to 3pm):

# sar -R ALL -f /var/log/sa/sa10 -s 07:00:00 -e 15:00:00

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