What is This error
In Linux based Os's there are resource limits are specified for user/process to ensure fair usage of resources and for security reasons.If a resource usage of of user/process try exceed the specified limit it was prevented by the OS.
How to see this limits
By using ulimit command we can examine this parameters at the global level.
[user@localhost ~]$ ulimit -a core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 0 file size (blocks, -f) unlimited pending signals (-i) 7281 max locked memory (kbytes, -l) 64 max memory size (kbytes, -m) unlimited open files (-n) 1024 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) 819200 real-time priority (-r) 0 stack size (kbytes, -s) 8192 cpu time (seconds, -t) unlimited max user processes (-u) 4096 virtual memory (kbytes, -v) unlimited file locks (-x) unlimitedto see this details in a more specified way we can use /proc folder with relevant process id.
[user@localhost ~]$ sudo cat /proc/989/limits Limit Soft Limit Hard Limit Units Max cpu time unlimited unlimited seconds Max file size unlimited unlimited bytes Max data size unlimited unlimited bytes Max stack size 8388608 unlimited bytes Max core file size 0 unlimited bytes Max resident set unlimited unlimited bytes Max processes 7281 7281 processes Max open files 1024 4096 files Max locked memory 65536 65536 bytes Max address space unlimited unlimited bytes Max file locks unlimited unlimited locks Max pending signals 7281 7281 signals Max msgqueue size 819200 819200 bytes Max nice priority 0 0 Max realtime priority 0 0 Max realtime timeout unlimited unlimited usto see file descriptor limit currently used by the process
[user@localhost ~]$ sudo ls -al /proc/1181/fd | wc -l 17Using lsof command sometimes not provide accurate detail because it count all the files involves with the process even .so files.
How to increase this limits
In the OS level
Enter value like the following to the /etc/sysctl.conf.(Maximum number can be allowed is 65535 because it is the highest number which can be represented by an unsigned 16-bit binary number) and reload the kernel variables.
[user@localhost ~]$ cat /etc/sysctl.conf # System default settings live in /usr/lib/sysctl.d/00-system.conf. # To override those settings, enter new settings here, or in an /etc/sysctl.d/<name>.conf file # # For more information, see sysctl.conf(5) and sysctl.d(5). fs.file-max=20000 [user@localhost ~]$ sudo sysctl -p [sudo] password for user: [user@localhost ~]$ sysctl fs.file-max fs.file-max = 20000In the user level enter the new configuration to /etc/security/limits.conf file using following format.
user soft nofile 10000 user hard nofile 8000
