Resource Management : Pmap

pmap command can be used to understand virtual memory mapping of an UNIX process, memory usage, and attributes of memory area etc. View the memory map of a process [root@vx111a test]# pmap 4226 4226:   /bin/bash ./top.sh 006db000    108K r-x--  /lib/ld-2.5.so 006f6000      4K r-x--  /lib/ld-2.5.so 006f7000      4K rwx--  /lib/ld-2.5.so 006fa000  ...

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Magic SysRq

On A System that is very slow but not dead, there is a way in linux to send commands to the kernel directlty.This can be done using the SysRq.This means even if you cant login , you can either recover from the system or either re-boot in such way that causes less risk. The magic SysRq key is a key combination in the Linux kernel which allows the user to perform various low level commands regardless of the system’s state. The...

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Resource Management : Strace

Strace is a command available in linux which helps in debugging and troubleshooting the execution of a executable ( command or a process).Strace also tells you what is going with a program at this point. It can tell you what system calls the program is using and whether they pass or fail. Strace monitors the system calls and signal of a Specific program. This command is mainly helpful when we don't have a Source code and would like...

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Resource Management : Lsof

lsof stands for 'List of Open Files’. This command is used to report all the open files and the process that currently opened them. Open files include disk files, pipes, network sockets and devices opened by all processes. This can be very use full when we see issue which unmouting a file system. We can trace out which files are being open and can kill them to unmount. A Basic execution of lsof gives , [root@vx111a test]#...

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Resource Management : Fuser

Fuser is a utility available in Linux which shows what processes are using a file ,file system and socket. The output of "fuser" may be useful in diagnosing "resource busy" messages arising when attempting to unmount file systems. Check Process That are currently using the Current Directory [root@vx111a test]# fuser . .: 3394c 3806c 3807c [root@vx111a test]# ps ux | grep vi root 3540...

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