Comment 4 for bug 821603

> Did you try setting it to a non-zero value other than the default, if 1048676 was the default?

I have tried this now and it behaves like 0.

> Also, did you check that the value isn't getting overwritten by a later line in the same or a later config file in /etc/sysctl.d?

Yes, sysctl is even telling me that it wanted to apply 0:

root@ubuntu:~# sysctl -p
vm.dirty_background_bytes = 0
root@ubuntu:~# sysctl -a | grep 'vm\.dirty_background_bytes'
vm.dirty_background_bytes = 1048576