@4ad would like fsnotify to support FEN on Solaris.

While each file & directory requires an event source, the limits are much higher than kqueue:

The default limit is 64k event sources per event port per process.
The default limit for the number of event sources per system is
2^31.

The default limit for the number of event ports per process is 8k.
The default limit for the number of event ports per system is 64k.

Reference

• File Events Notification
• DTrace on Solaris can watch recursively.