Error:
Hard limit value of the file descriptors on this system is set to 1024
Explanation:
The Directory Server is multi-threaded and efficiently handles many simultaneous requests and large numbers of connections.
Most of the time, the only limit on Directory Server threads is whatever limit the operating system imposes on the number of file descriptors available in the whole system and per process. The Directory Server uses file descriptors in a range of directory operations — logging, chaining, replication, client connections, and indexes. Adjusting the number of file descriptors for the Directory Server, then, can improve how well it handles large loads for a variety of operations.
Resolution:
First of all check the current system limit for the file descriptors:
# cat /proc/sys/fs/file-max
If the setting is lower than 64000, edit the /etc/sysctl.conf file, and reset the fs.file-max parameter:
# vi /etc/sysctl.conf fs.file-max=65536
To update the system with the new entry in sysctl.conf
# sysctl -p
Verify the updated changes in your system
# sysctl -a | grep fs.file-max
Once you have updated the max file deciptor value in a system, you need to update the hard and soft limit per user descriptor value.
To check the limit for File descriptor on user use this command
# su - "username"
# su - deepak
# ulimit -n
To check the hard limit
# ulimit -Hn
To check the soft limit
# ulimit -Sn
Now to change the limit value , follow these instruction as root user
# vi /etc/security/limits.conf
(Add the following entry)
deepak hard nofile 4096
deepak hard nofile 10240
NOTE: Do not set the hard limit for the Directory Server user equal to (or higher than) the maximum number of file descriptors assigned to the system itself in /proc/sys/fs/file-max. If the hard limit is too high and the user users all of those file descriptors, then the entire system runs out of file descriptors.
verfiy the new limits on the user
# su - deepak
# ulimit -Hn
# ulimit -Sn
Follow the below links for more tutorials
How to configure DHCP in Linux
How to change user Password Expiry, Home Directory etc in Linux