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System Resources

CPU Management

1. Using SAR Utility

It can be used to monitor system's resources like CPU usage, Memory utilization, Disk usage and more.

Sar -u 1 3

Here -u reports CPU. Use the man command to know more. The above command gives the CPU utilization at an interval of 1 seconds 3 times.

2. Using TOP command

The Unix top command is useful for monitoring systems continuously for processes that take more system resources like the CPU time and the memory.

  • On RHEL and Ubuntu:
top

%Cpu(s): 0.3 us, 0.7 sy, 0.0 ni, 97.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
Check for the idle processes [id]. Here, The idle is at 97.3, which means 97.3 - 100 = Current CPU Usage is 2.7%

3. Advanced Command

Warning

To be used only when understood how it works. This mostly works only on RHEL systems.

A=`mpstat | awk '$13~ /[0-9]+/{print 100-$13"%"}'`; echo "CPU Utilization - $A"

Action:

Once you have the necessary information, please email the POC and request that they housekeep the CPU usage to keep it optimally below the threshold value.

Memory Management

1. Using FREE Command

This command displays overview of the system's memory and swap, aka virtual memory, usage.

On RHEL or Ubuntu:

free -m

Here, Instead of -m, which shows the values in MB, you could use -g for GB or -h for human-readable format.

  • on AIX:
svmon -O unit=GB

This command runs the svmon tool and displays memory usage statistics in gigabytes (GB)

2. Using TOP Command

This flag combined with the TOP,

  • RHEL and Ubuntu:
top -o %MEM

Here -o %MEM flag is used to sort by Memory usage.

or

top -o SWAP

Here -o SWAP flag is used to sort by Paging usage.

  • On AIX:
topas

3. Advanced Command

Warning

To be used only when understood how it works.

echo ""; echo -e "\e[1mMemory Status: \e[0m"; free -m; echo ""; echo -e "\e[1mCurrent Memory Usage: \e[0m"; free | awk '/Mem/ {printf "%.2f%%\n", $3/$2 * 100}'; echo""; echo -e "\e[1mCurrent Swap Usage: \e[0m"; free | awk '/Swap/ {printf "%.2f%%\n", $3/$2 * 100}'; echo""; echo ""

Action:

Once you have the necessary information, please email the POC and request that they housekeep the Memory or Swap/Paging usage to keep it optimally below the threshold value.

Disk Management

1. Using DF

df displays the amount of space available on each file system. Using -h [human-readable format] helps in displaying the sizes in MB or GB.

  • RHEL and Ubuntu
df -h

Here -h means human readable format.

  • AIX
df -m

On AIX, use can use flags like -m to show sizes in MBs or -g to show in GB.

2. Using DU

du command displays disk usage within directories and files.

  • RHEL and Ubuntu
du -sh *
  • AIX
du -sm *

Using du with such flags, -s for summarize and -h for human-readable format, and aesterisk is a wildcard that matches all files and directories in the current directory. Note that AIX doesn't support the -h flag, Hence different commands below.

3. Advanced Command

Warning

To be used only when understood how it works.

Used to remove file which are older then 90 days within this path: "/var/spool/clientmqueue/"

find /var/spool/clientmqueue/ -type f -mtime +90 -exec rm {} \;

Action:

Filesystems such as /, /data, /boot, and /var are supported by CMS-Linux. Consequently, any alerts generated for these filesystems will be managed by CMS-Linux.

For other filesystems:
Collect the required data, email the POC with the relevant artifacts, and request that they perform housekeeping on the filesystem utilization to maintain it optimally below the defined threshold value.