At startup, Nexus may report a log message similar to the following:
No adverse behavior may be noticed despite this message. However, something may go wrong at a future point, and the result could be disastrous.
Given the number of services embedded in NXRM (orient, elasticsearch, etc.) you could quickly run out of file descriptors if the limit is set to low, and in some circumstances that could lead to files not getting written out which could eventually lead to instability or even corruption issues.
Nexus 3.x users should up their file descriptor limit to 65536 - this applies to Linux and OSX systems only and is considered a safe maximum value which should avoid bumping up against any system level ulimit defaults.
Given elasticsearch itself recommends a file descriptor limit of 65536 or higher in https://www.elastic.co/guide/en/elasticsearch/reference/current/file-descriptors.html, the Nexus system requirements are also requiring upping the ulimit to this recommended minimum value.