Google's Got Your BackupGoogle's Got Your Backup

Cloud computing remains somewhat suspect when it comes to security, and not without reason. Many noteworthy cloud services, like Google's Gmail, are only a password away from being pilfered, though enhanced security options are available.

Any time a business hands its data over to a third-party, some wariness is warranted.

But cloud security in some areas goes beyond what's available using on-premises IT. Or at least it's a better deal.

Take Google Apps, which includes Gmail, Google Docs, Google Calendar, Google Groups, Google Sites, and Google Video, for $50 per user annually. Among its less-heralded features is automatic backup and disaster recovery, at no extra cost.

In a blog post on Thursday, Rajen Sheth, senior product manager for Google Apps, explains that Google Apps customers don't need to worry about backups or disaster recovery.

Disaster recovery, he explains, is usually measured in terms of RPO (Recovery Point Objective) and RTO (Recovery Time Objective). RPO represents the amount of acceptable data loss in the event of an outage -- the gap between backups -- and RTO represents the acceptable amount of downtime before service is restored.

For large companies running Storage Area Networks (SANs), RPO and RTO targets are often an hour or less, explains Sheth, and that kind of disaster response usually costs a lot.

"For Google Apps customers, our RPO design target is zero, and our RTO design target is instant failover," he says in the blog post. "We do this through live or synchronous replication: every action you take in Gmail is simultaneously replicated in two data centers at once, so that if one data center fails, we nearly instantly transfer your data over to the other one that's also been reflecting your actions. Our goal is not to lose any data when it's transferred from one data center to another, and to transfer your data so quickly that you don't even know a data center experiences an interruption."

Sheth says that Google's live replication was one of the reasons that the City of Los Angeles decided to move from on-premises e-mail to Google Apps.

Sheth acknowledges that no system is perfect. But imperfection is part of Google's plan.

"We design for failure," said Sheth in an e-mail. "We operate on such a large scale that there are always servers and server racks that need to be maintained and upgraded. Our infrastructure is designed to give us the flexibility to take action when we need to without impacting users. For example, most corporations take down their servers for a set of time to conduct planned maintenance. We just switch people over to a new data center, and they never notice."