Using System Activity Report (SAR) in Linux For Present & Past System Performance Monitoring

Using System Activity Report (SAR) in Linux For Present & Past System Performance Monitoring:
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System Activity Report (sar) is a Unix System V-derived system monitor command used to report on various system loads, including CPU activity, memory/paging, interrupts, device load, network and swap space utilization. Sar uses /proc filesystem for gathering information.

# dnf repolist

# dnf install sysstat -y

# systemctl start sysstat

# systemctl enable sysstat

It collects the data every 10 minutes and generate its report daily. Below crontab file is responsible for collecting and generating reports.

# vim /etc/cron.d/sysstat
# Run the tool at every 10 minutes automatically.
*/10 * * * * root /usr/lib64/sa/sa1 1 1
# Generate a daily summary of process accounting at 23:55
55 23 * * * root /usr/lib64/sa/sa2 -A

Below is the Config File of SysStat ( sar command ).
# cat /etc/sysconfig/sysstat

Example:1 Generating CPU Report on the Fly 6 times at every 3 seconds.
# sar 3 6

If the %I/O wait is more than zero for a longer period of time then we can consider there is some bottleneck in I/O system (Hard disk or Network).

Example:2 Saving sar output to a file using -o
# sar 2 5 -o /tmp/data

use “sar -f filename” to display the reports.
# sar -f /tmp/data

Example:3 Generating Memory Usage report using -r option in the sar command which is used to generate memory usage report.
# sar -r 3 6
kbcommit & %commit is the overall memory used including RAM & Swap

Example:4 Generating Paging Statistics Report using -B
-B option in the sar command is used to display paging statistics.
# sar -B 3 6
In the report majflts/s shows the major faults per second means number of pages loaded into the memory from disk (swap), if its value is higher then we can say that system is running of RAM.

%vmeff indicates the number of pages scanned per second, if it’s vaule is 100 % its is consider OK and when it is below 30 % then there is some issue with virtual memory. Zero value indicates that there is no page scanned during that time.

Example:5 Generating block device statistics report using -d
-d option in the sar command is used to display the block device statistics report. Using option -p (pretty-print) along with -d make the dev column more readable, example is shown below :
# sar -d -p 2 4

Example:6 Generating Network statistic report using -n
-n option in the sar command is used to generate network statistic report. Below is the synatx :
# sar -n {keyword} or {ALL}

To generate all network statistic report use below command :
# sar -n ALL

Example:7 Reading SAR log file using -f
As we have discuss that sar logs files are kept under /var/log/sa/saDD, using -f option in sar command we can read the log files.
# sar -r -f /var/log/sa/sa12
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[PraveenKumar-enri]

Nicely explained, relly helpful for beginners

[artsy-anamika]

How to find out and store process name using sar command?

[lulbdiw]

Sir can you also make a video explanation the parameter for network and device and cpu and memory explaining the Statistics for low performances system or high utililzed system where where we can get to know what is needed to increase or get added like cpu or bandwidth or memory.

[psawantfeb]

How to measure cpu utilisation.
And send alet if utilisation value is above 70% atleast for 15 min then generate alert

[umeshtrivedi]

Very well explained.
How can i get notes you're using in video ?

[pratimam]

how to get the data from last six months of the CPU?

[surajdhanurkar]

is it possible to get 2 years back system activity report from sar

[hitman]

I will give free training on YouTube why are you paid YouTube video