I am trying to generate coredump for a particular pid.
I tried to change the core file size limit using ulimit, but it will change only in /proc/self/limits ( which is for shell).
So how do i edit it for particular pid?
Bascially i have to change "Max core file size=unlimited"
Note:
1)Our linux version dont have prlimit.
2)Even the below command didnt help
echo -n "Max core file size=unlimited:unlimited" > /proc/1/limits
Thanks,
prlimit
if you want to modify core_file limit, you can type
prlimit --pid ${pid} --core=soft_limit:hard_limit
the help page of prlimit is :
Usage:
prlimit [options] [-p PID]
prlimit [options] COMMAND
General Options:
-p, --pid <pid> process id
-o, --output <list> define which output columns to use
--noheadings don't print headings
--raw use the raw output format
--verbose verbose output
-h, --help display this help and exit
-V, --version output version information and exit
Resources Options:
-c, --core maximum size of core files created
-d, --data maximum size of a process's data segment
-e, --nice maximum nice priority allowed to raise
-f, --fsize maximum size of files written by the process
-i, --sigpending maximum number of pending signals
-l, --memlock maximum size a process may lock into memory
-m, --rss maximum resident set size
-n, --nofile maximum number of open files
-q, --msgqueue maximum bytes in POSIX message queues
-r, --rtprio maximum real-time scheduling priority
-s, --stack maximum stack size
-t, --cpu maximum amount of CPU time in seconds
-u, --nproc maximum number of user processes
-v, --as size of virtual memory
-x, --locks maximum number of file locks
-y, --rttime CPU time in microseconds a process scheduled
under real-time scheduling
Available columns (for --output):
DESCRIPTION resource description
RESOURCE resource name
SOFT soft limit
HARD hard limit (ceiling)
UNITS units
For more details see prlimit(1).
I always do this with ulimit command:
$ ulimit -c unlimited
On my Linux distro (ubuntu 16.04), core files are left on this directory:
/var/lib/systemd/coredump/
If your distro is based on systemd, you can setup this directory by modifiying pattern on this file:
$ cat /proc/sys/kernel/core_pattern
Please, read this info:
$ man 5 core
Check information related with /proc/sys/kernel/core_pattern.
As suggested previously, you can define the directory where all your core files are dumped, modifying the content of this file with "echo" command. For example:
$ echo "/var/log/dumps/core.%e.%p" > /proc/sys/kernel/core_pattern
This will dump all cores on /var/log/dumps/core.%e.%p, where %e is pattern for the executable filename, and %p pattern for pid of dumped process.
Hopefully you can play with this to customize your own needs.
Related
There are 3 ways to set limits of number of files and sockets on Linux:
echo "100000" > /proc/sys/fs/file-max
ulimit -n 100000
sysctl -w fs.file-max=100000
What is the difference?
What is the most correct way to set limits of number of files on Linux?
sysctl is an interface for writing to /proc/sys and so does the same as echoing directly to the files. Whereas sysctl applies across the whole filesystem, ulimit only applies to writes from the shell and processes started by the shell.
I have to execute a .jar, and I need to use ulimit before this execution, so I wrote a shell script:
#!/bin/sh
ulimit -S -c unlimited
/usr/java/jre1.8.0_91/bin/java -jar /home/update.jar
But the ulimit seems to be ignored, because I have this error :
java.lang.InternalError: java.io.FileNotFoundException: /usr/java/jre1.8.0_91/lib/ext/localedata.jar (Too many open files)
If you want to change the maximum open files you need to use ulimit -n.
Example:
ulimit -n 8192
The -c option is changing the core file size (core dumps), not the maximum open files.
You need to apply the ulimit to the shell that will call the java application.
I try to get the output of the top 5 processes in a Linux system. I'm expecting to get the percentage of processor (CPU) used but I'm a little worried about if the command that I'm using gets the CPU or the RAM; what is the output?
ps -A --sort -rss -o comm,pmem | head -n 6
The man documentation of ps indicates that the output is the process, but I'm suspecting that is the RAM memory. Could you clarify the output for me, please?
It's a process sorting by rss which is resident set size - memory usage - and then showing you the command and percentage memory usage. Header line and top 5 processes.
For an explanation of what RSS actually is, see this answer on unix: https://unix.stackexchange.com/questions/35129/need-explanation-on-resident-set-size-virtual-size
To get the top 5 by CPU load as you asked:
ps -A --sort -pcpu -o comm,pmem,pcpu | head -n 6
How to get the information of a specific process given its process ID using the command 'ps' in Linux. I also want to get the proportion of memory the process occupies.
Is that 'ps processID' ?
You could use
pmap $PID
or perhaps
cat /proc/$PID/maps
and/or
cat /proc/$PID/status
See proc(5) for details.
ps -o pmem h -p processID
pmem: Ratio of the process's resident set size to the physical memory on the machine, expressed as a percentage.
I need some command line utility able to run specified command and measure process group memory usage at peak and average (RSS, virtual and shared). As I understand that should be a combination of ptrace(2) and libprocps, but I can't find anything similar.
Any ideas?
/usr/bin/time -f "max RSS: %MKb" <command>
See man time for more details.