Gmail went down ... Everyone Panic!

I guess that Gmail went down sometime the other day, and it caused the world to go into panic. It was down for 100 minutes according to many sites. Reference the OFFICIAL GOOGLE BLOG for more information. According to google this is what happened in summary:

Google took a small fraction of Gmail's servers offline to perform routine upgrades. They say that they do this all the time, and Gmail's web interface runs in many
locations and just sends traffic to other locations when one is offline. However, in this case they had slightly underestimated the load placed on the request routers — servers which direct web queries to the
appropriate Gmail server for response. At about 12:30 pm Pacific a few of the
request routers became overloaded and in effect told the rest of the system
"stop sending us traffic, we're too slow!". This transferred the load onto the
remaining request routers, causing a few more of them to also become overloaded,
and within minutes nearly all of the request routers were overloaded. As a
result, people couldn't access Gmail via the web interface because their
requests couldn't be routed to a Gmail server. IMAP/POP access and mail
processing continued to work normally because these requests don't use the same
routers.The Gmail engineering team was alerted to the failures within seconds
(we take monitoring very seriously). After establishing that the core problem
was insufficient available capacity, the team brought a LOT of additional
request routers online (flexible capacity is one of the advantages of Google's
architecture), distributed the traffic across the request routers, and the Gmail
web interface came back online.What's next: We've turned our full attention to
helping ensure this kind of event doesn't happen again. Some of the actions are
straightforward and are already done — for example, increasing request router
capacity well beyond peak demand to provide headroom. Some of the actions are
more subtle — for example, we have concluded that request routers don't have
sufficient failure isolation (i.e. if there's a problem in one datacenter, it
shouldn't affect servers in another datacenter) and do not degrade gracefully
(e.g. if many request routers are overloaded simultaneously, they all should
just get slower instead of refusing to accept traffic and shifting their load).
We'll be hard at work over the next few weeks implementing these and other Gmail
reliability improvements — Gmail remains more than 99.9% available to all users,
and we're committed to keeping events like today's notable for their rarity