Fix "Too many open files" Java IO exception

Issue:

Getting "java.io.IOException: Too many open files" in Solr.

Environment:

Solr (Any version)

Resolution:

Perform the following steps to fix this issue.

Step 1. Edit /etc/sysctl.conf

fs.file-max = 9999999 (to a high integer number if its set to low value)

To update the value do sysctl -p  to apply the changesand then sysctl -a | grep file-max to verify

Step 2. To change the ulimit setting, edit the file /etc/security/limits.conf and set the hard and soft limits.

*     soft   nofile         65535

*     hard  nofile         65535

Step 3. Reboot

To verify

#cat /proc/sys/fs/file-max

9999999

#sysctl -a | grep fs.file-max

fs.file-max = 9999999

#ulimit -n

65535