Every LINUX system admin must now these tools to perfectly manage and monitor the server performance. Try these built-in commands and a few add-on tools. Most Linux distributions are equipped with tons of monitoring. These tools provide metrics which can be used to get information about system activities. You can use these tools to find the possible causes of a performance problem like under given;
- CPU Usage
- Hard Disk Usage
- RAM Usage
- Network Problem
PS – Displays the Processes
ps command will displays a list of running processes. There are number of flags given to view specific process like;ps –aux | more this command will show all the processes along with user ID and process ID. see the picture. For more information check the manual pages of ps command.
FREE – Memory Usage
free command displays the total amount of free and used physical and swap memory in the system, as well as the buffers used by the kernel. The shared memory column should be ignored; it is obsolete.
free [-b | -k | -m | -g] [-o] [-s delay ] [-t] [-V]
- TOP – Displays 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.See the manual pages for further details.
VMSTAT – Report virtual memory statistics
vmstat reports information about processes, memory, paging, block IO, traps, disks 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. See the manual pages for further details.
W – Show who is logged on and what they are doing?
w command 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. See the manual pages for further details.
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.
PMAP – Report memory map of a process
The pmap command reports the memory map of a process or processes.
-x extended Show the extended format.
-d device Show the device format.
-q quiet Do not display some header/footer lines.
-V show version Displays version of program.
NETSTAT – Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships
netstat prints information about the Linux networking subsystem. The type of information printed is controlled by the first argument.
See the manual pages for more details;
SS – Utility to investigate sockets
ss utility will displays one line socket information. See the manual pages for more details;
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. If the command is issued without any command-line options, the program comes up in interactive mode, with the various facilities accessed through the main menu.
TCPDUMP – Dump traffic on a network
tcpdump prints out a description of the contents of packets on a network interface that match the Boolean expression. It can also be run with the -w flag, which causes it to save the packet data to a file for later analysis, and/or with the -r flag, which causes it to read from a saved packet file rather than to read packets from a network interface. In all cases, only packets that match expression will be processed by tcpdump.
STARCE – Trace system calls and signals
In the simplest case strace runs the specified command until it exits. It intercepts and records the system calls which are called by a process and the signals which are received by a process. The name of each system call, its arguments and its return value are printed on standard error or to the file specified with the -o option. Students and Hackers man can find this tool as a very useful tool.
NAGIOS – Server And Network Monitoring
nagios is a popular open source computer system and network monitoring application software. You can easily monitor all your hosts, network equipment and services. It can send alert when things go wrong and again when they get better. FAN is "Fully Automated Nagios". FAN goals are to provide a Nagios installation including most tools provided by the Nagios Community. FAN provides a CDROM image in the standard ISO format, making it easy to easily install a Nagios server. Added to this, a wide bunch of tools are including to the distribution, in order to improve the user experience around Nagios.
