Understanding Resources From OS perspective
All activities in a computer can be tracked by Linux Commands
Process
| Command | Usage |
| ps -eaf | grep ProcessName | find the pid , ppid of the process |
| ps -eaf | grep ProcessName | find the binary path of the process |
| ps -eaf | grep ProcessName | Find the user under which the process is running |
| pidof ProcessName | pid of the running process |
| lsof -p “pidof the the process” | gives all the resources held by the process(files, ports, binaries, streams) |
| fuser FileName | gives the pid of the process holding the file |
Process Interaction with other resources
| Interaction |
Command |
| Process interaction with CPU And RAM | top -p pidOfTheProcess |
| To list all the resources | lsof -p pidofProcess. |
| To list all network ports acquired by process | netstat -pant | grep 2043 |
| To find disk io done by process | iotop -p 2043 |
[addToAppearHere]
Storage :
| Commands | Usage |
| lsblk | In detail info of all Hardisk attched |
| sudo fdisk -l | Info of Proc FileSystem And Disk FileSystem |
| df -hk | Dir Usage |
| /etc/fstab | File which holds info about the hardisk attached |
| iostat -d -x 5 | Live I/O info of the hardisk |
| lsblk -o NAME,PHY-SeC | Physical Sector of each hardisk |
| hdparm -I /dev/sdX | All info about the Hardisk (Manufacturer, configuration) |
Network:
| Commands | Usage |
| ifconfig | All possible ways of network interfaces available |
| lsof -i | All host:port connectivity |
| netstat -i | I/O happening on network card |
| Iftop | Network Top to get live IO metrics |
| iptraf | Grpahical Interface to monitor Network IO |
| ifstat -t -i eth0 0.5 |
CPU
| Commands | Usage |
| sar -u 2 | All cpu Combined metrics |
| iostat -c -x 3 | All cpu Combined metrics |
| mpstat -P ALL | Individual Cores usage |
| top | CPU + RAM usage |
Swap Space
| Commands | Usage |
| sudo ps -eo min_flt,maj_flt,cmd | |
| /usr/bin/time -v ls /etc/passwd | Figures out swap used during comand execution |
| grep pgfault /proc/vmstat | Page Faults that has happened till now |
| cut -d ” ” -f 1,2,10,12 /proc/pid/stat /proc/pid/stat | Swap info about a running process |
OS page cache and Disk cache
Flushing out Page(OS) Cache
$ sudo sh -c ‘echo 3 >/proc/sys/vm/drop_caches’
Flush Disk Cache :
blockdev –flushbufs /dev/sda
hdparm -F /dev/sda