Cloud Backup Series

This post is one of a series regarding cloud backup.  See these links for more information concerning Unitrends cloud backup along with an overview of Vault2Cloud: Unitrends enterprise level cloud backup service.

Cloud Backup: Cloud Storage and Cloud Backup: The Problem

While there are a lot of different cloud-based computing solutions out there, what we’ll focus on in the remainder of these posts is cloud storage and cloud backup.  Cloud storage simply refers to the use of the cloud as a replacement for some NAS (Network Attached Storage) centralized storage – some vendors advertise their cloud storage as “your file server in the cloud.”  Cloud backup refers to the use of the cloud as a mechanism to protect data.

“Pure” cloud storage and cloud backup (where “pure” denotes using only the cloud instead of some type of on-premise mechanism coupled with the cloud) alone suffer from one drawback first and foremost: the aforementioned gap between on-premise and off-premise (cloud) performance due to the WAN used to connect the two.  Practically, the problem is that while the price per gigabyte of storage has been dropping at a tremendous rate with 7200RPM 1TB drives priced below $90 at the time this paper was being written – the rate at which the price per megabit per second of WAN bandwidth has dropped has been relatively sluggish.

For that reason some type of caching mechanism for both is needed.  For pure cloud storage, the typical mechanism is some type of local per-client replication – such that the data is replicated directly on the client where the data is being used as well as in the cloud.  This works as long as the change rate of the data is relatively low.

Pure online backup is offered by an ever-growing number of vendors.  And most of these online backup vendors do a credible job of backing up a few tens of gigabytes of data.  The real problem with online backup is recovery.  You might not care that it takes a month or more to ship your first terabyte up through the Internet to the online backup vendor.  However, most people don’t have a month to wait for that terabyte to be downloaded back from their online backup vendor when a hard drive or a complete system is lost.