Linux Performance Monitoring Tools

Linux Performance Monitoring Tools

1. top

top command will  display Linux tasks

The  top  program  provides  a dynamic real-time view of a running system. It can display system summary information as well as a list of tasks currently being managed by the Linux kernel. The types of system summary information shown and the types, order and size of information displayed for tasks are all user configurable and that configuration can be made persistent across restarts.

2.vmstat

vmstat report virtual memory statistics

vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.

The  first report produced gives averages since the last reboot. Additional reports give information on a sampling period of length delay. The process and memory reports are instantaneous in either case.

3. w

w show who is logged on and what they are doing.

w  displays  information about the users currently on the machine, and their processes.  The header shows, in this order,  the current time, how long the system has been running, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.

The following entries are displayed for each user: login name, the tty name, the remote host, login time, idle time, JCPU, PCPU, and the command line of their current process.

The  JCPU time is the time used by all processes attached to the tty.  It does not include past background jobs, but does include currently running background jobs.

The PCPU time is the time used by the current process, named in the "what" field.

4. who

who print information about users who are currently logged in

5. whoami

whoami print the user name associated with the current effective user ID

6. uptime

uptime tell how long the system has been running
uptime  gives  a one line display of the following information.  The current time, how long the system has been running, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.

7. free

Display amount of free and used memory in the system

8. ss

ss is a network monitoring utility,showing open,connected,listening ports

ss  is  used  to  dump socket statistics. It allows showing information similar to netstat. It can display more TCP and state informations than other tools.

9. netstat

Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

10. tcpdump

Dump traffic on a network. It is an online network monitoring utility

11. iostat

Report Central Processing Unit (CPU) statistics and input/output statistics for devices, partitions and network filesystems (NFS)

12. strace

trace system calls and signals

                    # strace ls    - Shows background process

13. iptraf

Interactive Colorful IP LAN Monitor

iptraf  is  an ncurses-based IP LAN monitor that generates various network statistics including TCP info, UDP counts, ICMP and OSPF information, Ethernet load info, node stats, IP checksum errors, and others.

You need to install this package

        # yum install iptraf

14. sar

Collect, report, or save system activity information

The sar command writes to standard output the contents of selected cumulative activity counters in the operating system. The accounting system, based on the values in the count and interval parameters, writes information the specified number of times spaced at the specified intervals  in seconds. If  the interval parameter is set to zero, the sar command displays the average statistics for the time since the system was started. If the interval parameter is specified without the count parameter, then reports are generated continuously. The collected  data  can  also  be saved  in the file specified by the -o filename flag, in addition to being displayed onto the screen. If filename is omitted, sar uses the standard system activity daily data file, the /var/log/sa/sadd file, where the dd parameter indicates the current day. By default  all  the  data available from the kernel are saved in the data file.

15. nmap

Network exploration tool and security / port scanner, It shows open ports