How do I monitor linux open file usage

Linux users are typically configured with a maximum number of files to be opened. This is describe at
based upon your installation method.

To monitor how many open files a user has one can run

lsof -u <user>

replacing with the linux username who started the Neo4j process.

To understand the limits for said one can also run

cat /proc/<processID>/limits

replacing with the linux processID for the running Neo4j process.

This will produce output similar to

cat /proc/5219/limits
Limit                     Soft Limit           Hard Limit           Units
Max cpu time              unlimited            unlimited            seconds
Max file size             unlimited            unlimited            bytes
Max data size             unlimited            unlimited            bytes
Max stack size            8388608              unlimited            bytes
Max core file size        0                    unlimited            bytes
Max resident set          unlimited            unlimited            bytes
Max processes             31357                31357                processes
Max open files            40000                40000                files