How To Check CPU Usage On AIX Systems

How to Check CPU Usage On AIX Systems:

This post will discuss about how a system administrator can check CPU usage for AIX systems in Production environment.

Steps:

1. Running Processes:

Check what all application related processes are running and which all are utilizing more CPU by running the TOPAS command.

# topas

Topas command will give you the CPU usage for each process.

There are many different topas commands which system admin can use to check CPU usage.

# topas –P

2. Memory Usage:

Check memory usage for each process utilizing high CPU by running the following command:

# svmon –p

This will show memory usage for each command.

3. Kill Processes not Required:

Kill the processes not in use by the application team in production environment in order to reduce the CPU usage. Be very careful while killing a process, be 100% sure that the process is not being used by any team member in live environment.

Applications become slow when the disk is more than 80% busy. Same thing can be checked using the following commands:

 # filemon

# nmon

# iostat

“You can refer to & study all these commands in detail on this blog in various other posts”

Performance tuning parameters can be used for tuning LV’s, PV’s.

Remember: AIX does not support FAT file system.

Additional information on AIX System Administration – II

This is a continuation to the Post “Additional Information on AIX System Administration – I”

• Fuser or lsof command is basically used to check why a file system is not getting unmounted.

             # fuser –u <file system>

Eg:

            # fuser –u /data

This command will list the process numbers and user login names of processes using the /data file system.

• /etc/resolv.conf is used to provide a list of nameservers and domains to search for hosts. This file is used to configure DNS client.
• /etc/netsvc.conf file is used to modify name resolution lookup order. It specify name resolution and host settings.
• Vmstat command gives system’s average CPU usage. Vmstat also gives information about number of system calls per second. It also provides information on performance bottlenecks.
• SAR also shows cpu usage for a particular processor. Command used is:

             # sar –u

• If a new fileset is installed to check what all files are installed, command used is:

             # lslpp –f <filename>

• ML (Management Level) is a collection of APARs.
• Kernel is always represented with logical device called Sys0.
• Perfagent tool is the package used for running performance tuning commands like svmon, filemon, tprof etc.
• Iptrace and tcpdump is used to identify packet sequence problems.
• Raid0 is used for hardware stripping and Raid1 is for Mirroring. (we will discuss more about Raid concept in later posts)

Till then,

Happy learning!

AIX Performance Tools

Top 5 AIX performance tools used are:

1.       Vmstat

2.       Topas

3.       Iostat

4.       Netstat

5.       Ps

Vmstat:

1. Gives:

i.      Traps

ii.      Virtual memory

iii.      Paging

iv.      CPU

v.      Number of interrupts per second

vi.      Kernel threads

Iostat:

1. Gives:

i.      CPU usage

ii.      i/o of disk, adapter, ttys

iii.      i/o subsystem

topas:

1. Gives:

i.      logical partition information (# topas -L)

ii.      processes(# topas -P)

iii.      file system(# topas -F)

iv.      disks(# topas -D)

For CPU Monitoring,

Admin can make use of:

1. netpmon
2. sar (sar -u)
3. topas

For memory monitoring,

Admin can make use of:

1. svmon
2. netpmon
3. filemon

Svmon and filemon are perfagent tools.

For I/O subsystem,

Admin can make use of:

1. fileplace
2. filemon

For Network,

1. tcpdump
2. netpmon

For processors and threads,

1. svmon
2. kdb
3. fuser
4. prof
5. truss

nmon will give entire OS performance information.

Mpstat: this command displays performance statistics of all logical CPU in system.

Lparstat: reports LPAR related information and statistics.

Traced based commands:

CPU Monitoring: tprof, trace, trcrpt

Memory: trace, trcrpt

i/o subsystem: trace, trcrpt

network: iptrace, trace, trcrpt

processes and threads: tprof, trace, trcrpt

SAR: System Activity Records: it collects reports and saves system activity information.

Happy Learning!