Linux - Basic Performance Monitoring Tools

FOR LINUX

Basic performance monitoring Tools

# cat /etc/redhat-release -> System Information

#uname â€"a -> To print system information

#runlevel -> To find the current and previous

system runlevel

o The proc directory is a place where one can gather all sorts of information directly from the kernel through the proc file- system. Let's look at CPU and memory information

#cd /proc ; # more cpuinfo , #more meminfo

o The lsmod command will give you the list of installed kernel modules.

#lsmod | more

#vmstat - command will give overall health of the system(RAM,I/O and CPU)

o Free is a nice utility which displays the total amount of physical RAM and swap on the system. It tells us what is used, free and shared.

#free

o Top is a nice character based tool that illustrates CPU, memory and process information

#top

o Finally, for those that prefer a graphical interface, the GNOME System Monitor is your tool. After getting X running, type in:

#gnome-system-monitor

TUNING

o Tuning the linux system using sysctl tool , which is used to configure kernel parameters. Let's pull out only the memory tunables by looking for tunables with the vm prefix

#sysctl -a | grep vm | more

vm.nr_hugepages = 0 vm.swappiness = 60 vm.nr_pdflush_threads = 2,

[continues...]

o Let's pick one of them: vm.swapiness, which defines the percentage of the kernel in physical memory which should swap memory into overall swap space. The lower one sets this, the more Linux will prefer to use physical RAM rather than swap. You should do this if you have plenty of RAM but too much paging. The default is 60, so we're going to change this to 20.

# sysctl -w vm.swappiness="20â€

You can make your changes permanent by editing

/etc/sysctl.conf.

Another tip I highly recommend is to run ckconfig. This utility tells you what services are currently running:

#chkconfig â€"list

Turn off any services that you are not using. You will find a lot more RAM available, as well as some additional CPU