By default, Linux only allocates 8192 watches for inotify, which is ridiculously low. And when it runs out, the error is also No space left on device, which may be confusing if you aren't explicitly looking for this issue.

vi /etc/sysctl.conf  增加  fs.inotify.max_user_watches = 262144

# sysctl -p
fs.file-max = 1020000
fs.inotify.max_user_watches = 262144