Costs vary widely among cloud backup providers, as do the methods of calculating them. Some offer "unlimited" amounts of storage for a monthly fee. Others, such as Amazon's Simple Storage Service (S3), charge a few cents per gigabyte per month to store data, with additional charges to upload or download data. Other vendors have sign-up fees or minimum monthly charges.
A major advantage of backing up to the cloud is that, in most cases, you can recover to any computer. This restore-anywhere feature may sound a bit risky, so most cloud services offer encryption as part of their packages.
Because most cloud backup services rely on the Internet to transfer data, there are practical size limits on how much data you can effectively back up. By its nature, cloud backups are slower than most LAN backups, although the speed depends almost entirely on the bandwidth of your connection. The other determining factor is the size of the backup window. With a fairly typical 6 Mbs connection speed and a weekend backup window, 1 TB or 2 TB of actual data transmitted may be pushing the limits. But most transmissions are far smaller, as differential or incremental backups only ship the changed data. The first backup, which is a full backup, takes far longer than subsequent backups.
And just because someone else is handling your backups doesn't mean you can forget about them. Analysts say it's important to trust your data to vendors who have the capability to protect
"Consider the class availability and disaster recovery capability," says Stephanie Balaouras, principal analyst at Forrester Research Inc., Cambridge, Mass. "Are they backing up to another site? If I were an enterprise-class company, I'd want to make sure my data was further protected."
Finally, consider the legal implications of where the data is being stored. "For European operations, you need to ask where the data center is located," says Balaouras. "Are you in violation of any national privacy laws by transmitting the data offsite?"
There are still plenty of things to like about tape, so it's unlikely it will disappear from remote offices completely. But it will undoubtedly become much less common as vendors develop replacement technologies at lower costs that enterprises can easily integrate into their existing backup infrastructure and operations.
BIO: Rick Cook specializes in writing about issues related to storage and storage management.
This was first published in March 2009