ulimit

set user limits.

The most common case is "Too Many Open Files" Error.

temporary fix

# check all limits
ulimit -a

# check number of files (nofile)
ulimit -n # default to 1024, meaning you can at most open 1024 files.

# set
ulimit -n 100000

permanent fix

Modify /etc/security/limits.conf, and add:

* soft nofile 100000
* hard nofile 100000