Imagine the sinking feeling of logging in to your Gmail account and finding it empty. That’s what happened to 0.02% of Gmail users yesterday, and we’re very sorry. 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.
I know what some of you are thinking: how could this happen if we have multiple copies of your data, in multiple data centers? Well, 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.
To protect your information from these unusual bugs, we also back it up to tape. Since the tapes are offline, they’re protected from such software bugs. But restoring data from them also takes longer than transferring your requests to another data center, which is why it’s taken us hours to get the email back instead of milliseconds.