For best product performance, increase the number of file
handles above the default of 1024 handles.
Before you begin
Important: Before you work with your Rational® product, increase the number of
file handles. Most Rational products
use more than the default limit of 1024 file handles per process.
A system administrator might need to complete this task.
About this task
Ensure that you complete the following steps correctly. If
this procedure is not completed correctly, your computer will not
start.
Procedure
- Log in as root. If you do not have root access, you need
to obtain it before continuing.
- Change to the etc directory.
Attention: If you decide to increase the number of file handles
in the next step, do not leave an empty initscript file on
your computer. If you do so, your computer will not start the next
time that you restart it.
- Use the vi editor to edit the initscript file in the etc directory.
If this file does not exist, type vi initscript to
create it.
- On the first line, type ulimit -n 4096.
The point is that 4096 is much larger than 1024, the default on most Linux computers.
Important: Do not set the number of handles too high, because
doing so can negatively affect system-wide performance.
- On the second line, type eval exec "$4".
- Save and close the file after making sure that you have
completed steps 4 and 5.
- Optional: Restrict the number of handles available
to users or groups by modifying the limits.conf file in the etc/security directory.
Both SUSE Linux Enterprise
Server (SLES) Version 9 and Red Hat Enterprise Linux Version 4.0 have this file by default.
If you do not have this file, consider using a smaller number in step
4 in the previous procedure (for example, 2048). Make this change
so that most users have a reasonably low limit on the number of open
files that are allowed per process. If you use a relatively low number
in step 4, it is less important to restrict the number of handles.
However, if you set a high number in step 4 earlier and you do not
establish limits in the limits.conf file, computer performance can
be reduced.
The following sample limits.conf file restricts
all users, and then sets different limits for others afterward. This
sample assumes that you set handles to 8192 in step 4.
* soft nofile 1024
* hard nofile 2048
root soft nofile 4096
root hard nofile 8192
user1 soft nofile 2048
user1 hard nofile 2048
Note that the
* in
the preceding example sets the limits for all users first. These limits
are lower than the limits that follow. The root user has a higher
number of allowable handles open, while number available to user1
is between the two. Make sure that you read and understand the documentation
contained in the limits.conf file before editing.