error that can thrown an application
The configured user limit (128) on the number of inotify instances has been reached, or the per-process limit on the number of open file descriptors has been reached.
or
Error: EMFILE: too many open files
edit /etc/sysctl.d/99-custom.conf
as follow to expand inotify watched to 1million ( each consume 1kb )
fs.inotify.max_user_watches = 1048576 # default: 30003
fs.inotify.max_user_instances = 524288 # default: 128
reload using follow
sysctl -p /etc/sysctl.d/99-custom.conf
related: filesystem watches