Stop synology internal fan fail error.

You need to login as root via telnet or ssh. Password is the same as admin and execute the following:

> echo 0 > /sys/module/ds211j_synobios/parameters/check_fan
> reboot

If you want to enable it back. Just execute the following

> echo 1 > /sys/module/ds211j_synobios/parameters/check_fan
> reboot