TOOLS
to Monitor Linux Performance
1. Top – Linux Process Monitoring
Linux Top command
is a performance monitoring program which is used frequently by many system
administrators to monitor Linux performance and it is available under manyLinux/Unix like
operating systems. The top command used to dipslay all the running and active
real-time processes in ordered list and updates it regularly. It display CPU
usage,Memory usage, Swap
Memory, Cache Size, Buffer Size, Process PID, User, Commands and much more. It also shows high memory and cpu utilization
of a running processess. The top command is much userful for system
administrator to monitor and take correct action when required. Let’s see top
command in action.
# top
Top Command Example
2. VmStat – Virtual Memory Statistics
Linux VmStat command
used to display statistics of virtual memory, kernerl threads,disks, system processes, I/O
blocks, interrupts, CPU activity and
much more. By default vmstat command is not available under Linux systems you
need to install a package calledsysstat that includes a vmstat program. The
common usage of command format is.
# vmstat
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
r b swpd free inact active si so bi bo in cs us sy id wa st
1 0 0 810420 97380 70628 0 0 115 4 89 79 1 6 90 3 0
3. Lsof – List Open Files
Lsof command used in many Linux/Unix like system that is used to display
list of all the open files and the processes. The open files included are disk
files, network sockets,pipes, devices and processes.
One of the main reason for using this command is when a disk cannot be
unmounted and displays the error that files are being used or opened. With this
commmand you can easily identify which files are in use. The most common format
for this command is.
# lsof
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
init 1 root cwd DIR 104,2 4096 2 /
init 1 root rtd DIR 104,2 4096 2 /
init 1 root txt REG 104,2 38652 17710339 /sbin/init
init 1 root mem REG 104,2 129900 196453 /lib/ld-2.5.so
init 1 root mem REG 104,2 1693812 196454 /lib/libc-2.5.so
init 1 root mem REG 104,2 20668 196479 /lib/libdl-2.5.so
init 1 root mem REG 104,2 245376 196419 /lib/libsepol.so.1
init 1 root mem REG 104,2 93508 196431 /lib/libselinux.so.1
init 1 root 10u FIFO 0,17 953 /dev/initctl
4. Tcpdump – Network Packet Analyzer
Tcpdump one of the most widely
used command-line network packet analyzer or packets sniffer program
that is used capture or filter TCP/IP packets
that received or transferred on a specific interface over a network. It also
provides a option to save captured packages in a file for later analysis.
tcpdump is almost available in all major Linux distributions.
# tcpdump -i eth0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
22:08:59.617628 IP tecmint.com.ssh > 115.113.134.3.static-mumbai.vsnl.net.in.28472: P 2532133365:2532133481(116) ack 3561562349 win 9648
22:09:07.653466 IP tecmint.com.ssh > 115.113.134.3.static-mumbai.vsnl.net.in.28472: P 116:232(116) ack 1 win 9648
22:08:59.617916 IP 115.113.134.3.static-mumbai.vsnl.net.in.28472 > tecmint.com.ssh: . ack 116 win 64347
5. Netstat – Network Statistics
Netstat is a command line tool
for monitoring incoming and outgoing
network packets
statistics as well as interface statistics. It is very useful tool for every
system administrator to monitor network performance and troubleshoot network
related problems.
# netstat -a | more
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:mysql *:* LISTEN
tcp 0 0 *:sunrpc *:* LISTEN
tcp 0 0 *:realm-rusd *:* LISTEN
tcp 0 0 *:ftp *:* LISTEN
tcp 0 0 localhost.localdomain:ipp *:* LISTEN
tcp 0 0 localhost.localdomain:smtp *:* LISTEN
tcp 0 0 localhost.localdomain:smtp localhost.localdomain:42709 TIME_WAIT
tcp 0 0 localhost.localdomain:smtp localhost.localdomain:42710 TIME_WAIT
tcp 0 0 *:http *:* LISTEN
tcp 0 0 *:ssh *:* LISTEN
tcp 0 0 *:https *:* LISTEN
6. Htop – Linux Process Monitoring
Htop is a much advanced
interactive and real time Linux process monitoring tool. This is much similar
to Linux top command but
it has some rich features like user friendly interface to manage process, shortcut
keys, vertical and horizontal view of the processes and much more. Htop is a third party
tool and doesn’t included in Linux systems, you need to install it using YUM package manager tool. For more
information on installation read our article below.
# htop
Htop Command Example
Screenshot
7. Iotop – Monitor Linux Disk I/O
Iotop is also much similar
to top command and Htop
program, but it has accounting function to monitor and display
real time Disk I/O and processes.
This tool is much useful for finding the exact process and high used disk
read/writes of the processes.
# iotop
Iotop Command Example
Screenshot
8. Iostat – Input/Output Statistics
IoStat is simple tool that
will collect and show system input and output storage device statistics. This tool
is often used to trace storage device performance issues includingdevices, local disks, remote disks such
as NFS.
# iostat
Linux 2.6.18-238.9.1.el5 (tecmint.com) 09/13/2012
avg-cpu: %user %nice %system %iowait %steal %idle
2.60 3.65 1.04 4.29 0.00 88.42
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
cciss/c0d0 17.79 545.80 256.52 855159769 401914750
cciss/c0d0p1 0.00 0.00 0.00 5459 3518
cciss/c0d0p2 16.45 533.97 245.18 836631746 384153384
cciss/c0d0p3 0.63 5.58 3.97 8737650 6215544
cciss/c0d0p4 0.00 0.00 0.00 8 0
cciss/c0d0p5 0.63 3.79 5.03 5936778 7882528
cciss/c0d0p6 0.08 2.46 2.34 3847771 3659776
9. IPTraf – Real Time IP LAN Monitoring
IPTraf is an open source
console-based real time network (IP
LAN) monitoring utility forLinux. It collects a variety of information such
as IP traffic monitor that passes over the network, including TCP flag
information, ICMP details, TCP/UDP traffic breakdowns, TCP connection packet
and byne counts. It also gathers information of general and detaled interface
statistics of TCP, UDP, IP, ICMP, non-IP, IP checksum errors, interface
activity etc.
IP Traffic Monitor
10. Psacct or Acct – Monitor User Activity
psacct or acct tools are very useful for monitoring each users
activity on the system. Both daemons runs in the background and keeps a close
watch on the overall activity of each user on the system and also what resources
are being consumed by them.
These tools are very useful for system administrators to track
each users activity like what they are doing, what commands they issued, how
much resources are used by them, how long they are active on the system etc.
11. Monit – Linux Process and Services Monitoring
Monit is a free open source
and web based process supervision utility that automatically monitors and
managers system processes, programs, files, directories, permissions, checksums
and filesystems.
It monitors services like Apache, MySQL, Mail, FTP, ProFTP,
Nginx, SSH and so on. The system status can be viewed from the command line or
using it own web interface.
Monit Linux Process
Monitoring
12. NetHogs – Monitor Per Process Network Bandwidth
NetHogs is an open source nice
small program (similar to Linux top command) that keeps a tab on each process
network activity on your system. It also keeps a track of real time network
traffic bandwidth used by each program or application.
NetHogs Linux Bandwidth
Monitoring
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