If you have been hearing paeans about cloud storage, you may think we are opening a can of worms in talking about latency. But, latency is a topic that cannot be ignored or brushed under the carpet. It is a factor that must be discussed, whether you are talking about offline storage or online storage.
Simply stated, latency is the time to respond. It is the interval between a request for a piece of information and its delivery. Cloud computing providers often gloss over this fact and hype up cloud computing as if it operates in an idealized abstract environment. Nevertheless, the abstraction helps us focus on “what can be achieved” as opposed to “What is being achieved” by way of reducing latency in networked environments. Even staunch advocates concede that latency in storage is a tricky problem that must be handled efficiently and effectively by the service provider.
The component elements of latency are significant, as each component delay can add to latency. The problem is made acute when data is distributed across a network that has a geographical spread. Research indicates that latency over the Internet is 100-1000 times higher than that of local networks and it is disconcertingly inconsistent; unpredictable. As a result, latency can cause data vanishings or data corruptions as data states are subjected to the problem of latency.
It follows that latency is a measure of application performance. It is the reason why we run applications close to the data on which they operate. The efficiency of the application is judged by how quickly it can read and write data that is being operated upon. When applications are local and data is cloud based, latency begins to matter in ways in which it never mattered before.
Further, while one can hope that the robust latency-aware application will resolve many of the latency issues, it does not always happen. Much of the latency that is encountered happens en route to the data repository. Some routers on the way may have a bad day and create latencies never experienced before.
Do you agree that it is important to understand the trade off before you commit to cloud based storage? The can of worms must be opened if you want to gain a realistic perspective on what you are getting! If your cloud based infrastructure is providing you with latency times that are acceptable, you can boldly trade off instantaneous data access for cost benefits, scalability, flexibility and centralized virtual infrastructure.