Short term versus long term “archiving”
This touches a vitally important point in the debate. Formerly, there was a distinction to be made between backup and archiving. But in my opinion, this distinction now needs revising to differentiate between (i) primary backup, (ii) short term archiving and (iii) long term archiving.
I described primary backup functions earlier but ‘short term archiving’ is a particularly strong use case for the cloud because it allows businesses to extend RPO by storing backup data on low cost, server-based object storage instead of using more expensive dedicated disk arrays. And it can achieve this with minimal impact upon their RTO. An example of this would be HPE CloudBank for HPE StoreOnce.
Space prevents me from going into all the details of how these HPE disk and cloud solutions complement each other, suffice to say that the benefits of HPE CloudBank (like deep integration with the secondary disk array; instant, on-demand, scale out flexibility; and speed of restoring backup data) would be hard to emulate using tapes in a vault. And that advantage probably holds for months and possibly a number of years if the data remains within the scope of being a target for backup. In a backup application, you may need instant, or near instant, access to random data. And if that is your need, you probably wouldn’t consider using tape in the first instance.
The italics hold the key to this distinction: if the data remains within the scope of being a target for backup. Arguably, this “short term archiving” isn’t really archiving at all, and might be better referred to as “deep backup”. A backup copy, one of many, destined to be overwritten is quite different from an archive copy, which is one of a kind and intended to be kept indefinitely. And as the importance and need for access fades, then based on currently available storage technologies, the pendulum still swings firmly back towards tape. And that statement holds true whether one is comparing tape to either the public cloud (AWS, Azure, Google) or private cloud solutions based on object storage systems.
The reason why I say there is a difference between short term archiving, and the extended periods for which I would consider tape, is similar to the one I was alluding to earlier on with my comparison of helicopters and jet fighters. Too often I see this backup-related use case simply referred to as ‘archiving’ when to my mind it’s a completely different task to the long term preservation of data. Short-term archiving to the cloud isn’t the same thing as long-term archiving to tape, and in my opinion, long-term archiving isn’t a strong use case for the cloud in the majority of cases. Tape still performs this role far better.
The longer your horizon - and businesses are forced by legislation and operational necessity to have very long horizons - the more effective tape becomes for reasons that I will consider in my next article.