Sometimes it’s hard to know how excited to be about the thing we’re now calling “the cloud.” In one sense, it’s not a particularly new idea: most of us have been using something we could reasonably call “cloud email” since the 1990s. Where’s your email stored? Doesn’t matter; it’s on a server somewhere. Of course, we could write off much of the modern cloud as “a server somewhere.” What’s changed is that everyone’s internet connections, even wireless internet connections over large areas, have made it possible to do a lot more with the system than just tiny fragments of data such as emails.
In a lot of the world, and particularly here in the UK, governments and corporations seem to have concluded that there’s a certain maximum amount of money people are willing to pay for an internet connection, and that making greater provision doesn’t necessarily mean more income for a service provider. That’s a shame, because it risks denying a number of possible futures for the internet in general and the cloud – let’s call it wide-area distributed computing – in particular. Even so, the capability available is now enough to mean anyone who encounters a short-notice and temporary need for several terabytes of storage can have it, even if a bit slowly on the average home broadband connection. Hopefully, that’ll be a statement we can come back to and laugh about in a few years.
One of the most popular and encouraging things about the cloud is that reliability isn’t the user’s problem. At some level, cloud storage still (almost invariably) boils down to some hard disks in a rack somewhere, but we can quite safely assume that those hard disks will be part of some larger reliability arrangements, whether a conventional disk array or, more likely, some sort of vast distributed object storage system, the details of which are hidden from, and irrelevant to, the user. Either way, there will be redundancy built in. Usually, those racks full of servers are kept in deliberately nondescript buildings on industrial estates round the world.
The simplest cloud provision might not, or in fact probably would not, even let a user know where the data is physically located; as we know from Amazon’s example, these places are somewhat security sensitive. Some cloud providers, though, offer the option to specifically keep data in more than one of these locations, perhaps several at once. That creates a really impressive degree of what the information technology industry terms “disaster recovery.” If something genuinely catastrophic happens – fire, flood, meteor strike, zombie apocalypse – then there’s a huge resistance to actually losing any data. Great! Now we don’t need that LTO drive, anymore, do we? – Read more