CrashPlan on Linux depends on the inotify kernel module to know when files update in real-time.
Inotify was merged into the 2.6.13 Linux kernel, so if you’re running a kernel equal to or newer than this, it’s already installed. If not, you’ll have to install it yourself. If inotify is installed, you may need to increase the number of watches that can be created.
The inotify module is govered by a property called max_user_watches. If you attempt to exceed the max number you’ll get the following error in the engine_error.log (but the process lives on).
inotify_add_watch: No space left on device
Any file not covered by a watch does not have real-time backup protection.
The default on my Ubuntu 11.04 box is 524288, which seems plenty sufficient for me. I have not experienced any issues, but if you find that you are, you may want to increase the watch value.
Updating the Watch Value
You can temporarily update the value with:
echo 1048576 > /proc/sys/fs/inotify/max_user_watches
You can update the value permanently by putting the following value in /etc/sysctl.conf and restarting:
For more information, see CrashPlan’s Forums.