How can I change the limit of 'Open Files' in ulimit?

thomas2004ch · 11-13-2009, 03:35 AM

I can use the ulimit -a to list the open file. The 'Open Files' is 1024.

Code:

-bash-2.05b$ ulimit -a
core file size        (blocks, -c) 0
data seg size         (kbytes, -d) unlimited
file size             (blocks, -f) unlimited
max locked memory     (kbytes, -l) 4
max memory size       (kbytes, -m) unlimited
open files                    (-n) 1024
pipe size          (512 bytes, -p) 8
stack size            (kbytes, -s) 10240
cpu time             (seconds, -t) unlimited
max user processes            (-u) 7168
virtual memory        (kbytes, -v) unlimited

Now I want to to increase the number. How can I do that?

Besides, I will change this 'Open Files' not for /root but for a sub-user.

thomas2004ch · 11-13-2009, 03:45 AM

I tried as follow but failed:

Code:

ulimit -n 5000

I got error:

Code:

ulimit: open files: cannot modify limit: Operation not permitted

maniannam · 11-13-2009, 06:16 AM

Quote:

Originally Posted by thomas2004ch

I tried as follow but failed:

Code:

ulimit -n 5000

I got error:

Code:

ulimit: open files: cannot modify limit: Operation not permitted

-n option is correct, but you have root access.

- maniannam

thomas2004ch · 11-17-2009, 03:37 AM

Quote:

Originally Posted by maniannam

-n option is correct, but you have root access.

I don't understand what you mean "you have root access" here. Do you mean I have to login as root? I can do this when I login as root. But this will change all the 'open files' to all users. This is what I don't want. I just want to change one of the user's 'open files'.

vishesh · 11-17-2009, 03:53 AM

I think , you must see
/etc/security/limits.conf

thanks

thomas2004ch · 11-17-2009, 04:10 AM

Quote:

Originally Posted by vishesh

I think , you must see
/etc/security/limits.conf

thanks

Here is my 'limits.conf'. How can I change?

Code:

[root@s003ap05-test ~]# cat /etc/security/limits.conf
# /etc/security/limits.conf
#
#Each line describes a limit for a user in the form:
#
#<domain>        <type>  <item>  <value>
#
#Where:
#<domain> can be:
#        - an user name
#        - a group name, with @group syntax
#        - the wildcard *, for default entry
#        - the wildcard %, can be also used with %group syntax,
#                 for maxlogin limit
#
#<type> can have the two values:
#        - "soft" for enforcing the soft limits
#        - "hard" for enforcing hard limits
#
#<item> can be one of the following:
#        - core - limits the core file size (KB)
#        - data - max data size (KB)
#        - fsize - maximum filesize (KB)
#        - memlock - max locked-in-memory address space (KB)
#        - nofile - max number of open files
#        - rss - max resident set size (KB)
#        - stack - max stack size (KB)
#        - cpu - max CPU time (MIN)
#        - nproc - max number of processes
#        - as - address space limit
#        - maxlogins - max number of logins for this user
#        - maxsyslogins - max number of logins on the system
#        - priority - the priority to run user process with
#        - locks - max number of file locks the user can hold
#        - sigpending - max number of pending signals
#        - msgqueue - max memory used by POSIX message queues (bytes)
#
#<domain>      <type>  <item>         <value>
#

#*               soft    core            0
#*               hard    rss             10000
#@student        hard    nproc           20
#@faculty        soft    nproc           20
#@faculty        hard    nproc           50
#ftp             hard    nproc           0
#@student        -       maxlogins       4
apache           -       nofile         5000
# End of file
[root@s003ap05-test ~]#

vishesh · 11-17-2009, 04:20 AM

root# vi /etc/security/limits.conf
(Enter following two lines at end of file by replaceing username )
<username> soft nofile 25
<username> hard nofile 30

--
here 25 and 30 are soft and hard limit corresponding.

Thanks

thomas2004ch · 11-17-2009, 05:09 AM

Quote:

Originally Posted by vishesh

root# vi /etc/security/limits.conf
(Enter following two lines at end of file by replaceing username )
<username> soft nofile 25
<username> hard nofile 30

--
here 25 and 30 are soft and hard limit corresponding.

Thanks

Thanks.

But if I do as follow:

Code:

 <username> - nofile 25

What is the difference?

vishesh · 11-17-2009, 05:12 AM

I think 25 will be your limit of open files.

Thanks

thomas2004ch · 11-17-2009, 05:16 AM

Quote:

Originally Posted by vishesh

I think 25 will be your limit of open files.

Thanks

Does this mean in my case both hard and soft has limit of 25?

vishesh · 11-17-2009, 05:21 AM

Yes, i am not 100% sure but i think both hard and soft will limit of 25.

Thanks