I support Google and the services they offer, including their mail service known as Gmail. But yesterday the system suffered another outage which according to their official web site was caused by an under estimate of usage. Which made me start to think. Is Google going to be able to handle the load in the future? If and when the company comes out with their Google OS and more people use their services, will Google finally show their Achilles heel and will there be more down time?
According to their blog site Google reps state the following:
Gmail’s web interface had a widespread outage earlier today, lasting about 100 minutes. We know how many people rely on Gmail for personal and professional communications, and we take it very seriously when there’s a problem with the service. Thus, right up front, I’d like to apologize to all of you — today’s outage was a Big Deal, and we’re treating it as such. We’ve already thoroughly investigated what happened, and we’re currently compiling a list of things we intend to fix or improve as a result of the investigation.
Here’s what happened: This morning (Pacific Time) we took a small fraction of Gmail’s servers offline to perform routine upgrades. This isn’t in itself a problem — we 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, as we now know, we had slightly underestimated the load which some recent changes (ironically, some designed to improve service availability) 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.
Though the blog entry goes on to state that Google is going to make sure that this doesn’t happen again, it does make wonder. If we continue to flock to Google services, will this one day bite us all in the butt?
What do you think?