Error: No space left on device ??

I have recently installed CrashPlan on my Linux (currently Ubuntu) server and noticed that I was getting some weird errors in my logs from console-kit-daemon:


console-kit-daemon[906]: WARNING: Failed to add monitor on '/dev/pts/0': No space left on device


All filesystems had plenty of free space and inodes (always one to remember, folks – “df -i” is your friend). Even stranger was the fact that I couldn’t run a “tail -f /var/log/syslog” since that was giving the same error:


tail: cannot watch `/var/log/syslog': No space left on device


A quick strace later and I found the culprit – the call to inotify_add_watch() was failing with ENOSPC. Some research turned up the fs.inotify.max_user_watches sysctl, so I solved the problem with:


sysctl -w fs.inotify.max_user_watches=16384
echo "fs.inotify.max_user_watches=16384" >>/etc/sysctl.conf


I guess the CrashPlan installer should probably suggest making this change for you.