Increase Total File Descriptors For System
When system performance on Linux is affected by using too many file descriptors, usually an error can be seen in the log file '(Too many open files)'. Although this affects the entire system, it is a fairly common problem.
To prevent Confluence from running out of filehandles you need to make sure that there are enough file handles available at the system level, and that the user you are running Confluence as is allowed to use enough file handles:
Run the command sysctl -a. If this is less than 200000, increase the number of file handles by editing /etc/sysctl.conf and changing the property fs.file-max to 200000. If there isn't a value set already for this property, you need to add the line fs.file-max=200000.
Then run sysctl -p to apply your changes to your system.