Internal: Increasing the maximum open file descriptor limit on Linux (Redhat website KB article)
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Below in the discussion is a copy of a Redhat website kb article saved to tech tip to preserve this information in case this article goes away from the RH website. Contents are for internal reference. We can send the Redhat URL (
http://kbase.redhat.com/faq/FAQ_80_1540.shtm) to customer if needed.
This information may be useful if a customer encounters the following lmgrd debug log error, which seems to indicate that there are too many files open by the user at one time:
...
12:13:14 (lmgrd) Can't open /usr/tmp/.flexlm/lmgrdl.28434, errno: 24
12:43:15 (lmgrd) Can't open /usr/tmp/.flexlm/lmgrdl.28434, errno: 24
13:13:16 (lmgrd) Can't open /usr/tmp/.flexlm/lmgrdl.28434, errno: 24
13:13:16 (lmgrd) Can't open /usr/tmp/.flexlm/lmgrdl.28434, errno: 24
...
13:19:59 (lmgrd) lmgrd will now shut down all the vendor daemons
13:19:59 (lmgrd) Shutting down idl_lmgrd
13:19:59 (lmgrd) Can't connect to the license server system. Shutdown idl_lmgrd failed.
13:19:59 (lmgrd) socket() call failed. (-57,17:24 "Too many open files")
13:19:59 (idl_lmgrd) daemon shutdown requested - shutting down
13:19:59 (lmgrd) Can't remove statfile /usr/tmp/.flexlm/lmgrdl.28434: errno No such file or directory
...Discussion:
The following is a copy of a Redhat web site knowledge-base article:
http://kbase.redhat.com/faq/FAQ_80_1540.shtm
Copyright © 2006 Red Hat, Inc. All rights reserved.
Issue: How do I set the maximum number of files allowed to be open on a system?
Resolution:The current setting for maximum number of open files can be viewed with the command:
ulimit -n
This number indicates the maximum number of files normal users (i.e. non-root) can have open in a single session. Note that for the root user, ulimit -n will sometimes output 1024 even after following the procedure to increase the maximum number of open files. This won't effect root's ability to open large numbers of files, as only normal users are bound by this value.
To increase the maximum number of open files beyond the default of 1024, two changes to the system may be necessary. In these examples, we will increase the maximum number of open files to the arbitrary value of 2048. All changes need to be made by the root user and users will need to log out and log back in before the changes will take effect.
Configure the system to accept the desired value for maximum number of open files Check the value in
/proc/sys/fs/file-max to see if it is larger than the value needed for the maximum number of open files:
# cat /proc/sys/fs/file-max
If the value isn't large enough, echo an appropriate number into the variable and add the change to
/etc/sysctl.conf to make it persistent across reboots. If the number is already larger than the value you wish to use, skip to step 2.
# echo 2048 > /proc/sys/fs/file-max
and edit
/etc/sysctl.conf to include the line:
fs.file-max = 2048
Set the value for maximum number of open files In the file /etc/security/limits.conf, below the commented line that reads #>domain< >type< >item< >value
* - nofile 2048
This line sets the default number of open file descriptors for every user on the system to 2048. Note that the "nofile" item has two possible limit values under the >type< header: hard and soft. Both types of limits must be set before the change in the maximum number of open files will take effect. By using the "-" character, both hard and soft limits are set simultaneously.
The hard limit represents the maximum value a soft limit may have and the soft limit represents the limit being actively enforced on the system at that time. Hard limits can be lowered by normal users, but not raised and soft limits cannot be set higher than hard limits. Only root may raise hard limits.
When increasing file limit descriptors, you may want to simply double the value. For example, if you need to increase the default value of 1024, increase the value to 2048 first. If you need to increase it again, try 4096, etc.