Google official apologized for the inconvenience and said that the lost data will be restored soon. Google released a statement saying that the Company keeps multiple copies of the data in multiple data centers and has the back-ups on offline tapes.
"The good news is that email was never lost and we"ve restored access for many of those affected. Though it may take longer than we originally expected, we're making good progress and things should be back to normal for everyone soon," said Ben Treynor, Google VP of engineering and site reliability czar, through Gmail blog.
"In some rare instances software bugs can affect several copies of the data. That"s what happened here. Some copies of mail were deleted, and we"ve been hard at work over the last 30 hours getting it back for the people affected by this issue," he added.
The reason behind the glitch was a storage software update released by Google. When they discovered the problem, Google immediately stopped the deployment of the new software and reverted to the old version.