10 November as Google AdSense Team sent will have couple of hours routine maintenance.
The exact mail is below
Tomorrow, November 10th, our engineers will be performing routine site maintenance. Although you won't be able to log in to your account between 10 am and 2 pm PST, we'll continue to serve ads to your pages and track all earnings in your account as usual.
Our international readers can expect the maintenance to start at the following times:
London - 6 pm Saturday
Kiev - 8 pm Saturday
Chennai - 11:30 pm Saturday
Manila - 2 am Sunday
Melbourne - 5 am Sunday
Some of you have been curious about what our engineers are up to during these maintenance periods. As you can imagine, running the system reliably requires constant nurturing. Some maintenance tasks are more fundamental to the way the system operates and are not easily done on the fly -- as a result, it's most efficient and helpful for us to take the system offline for a few hours. With that in mind, our engineers line up these tasks in advance and implement them during our regularly scheduled downtimes. We hope that these maintenance periods aren't too much of an inconvenience, and we appreciate your understanding.
Posted by Arlene Lee - AdSense Publisher Support