Cloud Storage 101 Episode 1 - What the heck is cloud storage?
Welcome to the first part of Cloud Storage 101, episode #1, "What the heck is cloud storage?". Unfortunately I don't have Lucasfilm's budget so I'm unable to provide a Star Wars entrance for this series, but even if I did, I'm not sure if you would consider it unique, corny, interesting, or what. In any case, in this series we're going to focus on providing a 5,000 foot view of various aspects of cloud storage. It won't be all encompassing, but nothing ever is when you're dealing with topics related to the cloud. I do encourage everyone to comment - good or bad - based on areas where you agree or disagree, see other values with cloud storage, and so on.
So, what the heck is 'cloud storage'?
Put simply, cloud storage is a product or service that allows you to store your information. Generally, cloud storage is provided by a third party and accessed over the Internet (Amazon S3, Microsoft Azure, AT&T Synaptic, Iron Mountain Digital) - these are commonly referred to as "public cloud storage" (owned by a service provider) - but there are also examples of cloud storage systems that are deployed behind your firewall (EMC Atmos) commonly called "private cloud storage" (owned by you). Cloud storage is similar to traditional storage found in your data center today in that it serves the purpose of storing data, but there are a few key differences.
1) Cloud storage is generally accessed through APIs (RESTful APIs that use HTTP, SOAP APIs, WebDAV). Some cloud storage services on the Internet provide access via file protocols (such as CIFS or NFS) or even FTP. Traditional storage is usually accessed through block protocols (iSCSI, FC/FCoE, all of which carry SCSI as payload) or file protocols (CIFS, NFS)
2) Cloud storage is inherently elastic. Given that most cloud storage services have their roots in providing data storage for really, really massively-scalable Internet applications - or roots in global object namespaces - it's no wonder that cloud storage can grow by simply adding nodes, without requiring data migration due to running out of space on a volume, as an example. This is largely due to the mindset of some of the revolutionary Internet giants wanting to come up with a way to eliminate operational costs from their business model and improve flexibility
3) Cloud storage can provide pay-as-you-use economics. For public cloud services, storage consumers are charged generally based on the amount of data they store, and how much data they access. For private cloud systems - and also legacy storage systems - there are the associated capital and operational costs associated with hardware purchase, maintenance, support, and other items, which are not a direct factor in the case of public cloud storage services (the provider deals with this, which of course impacts your data storage and data transfer pricing)
So why do people have an interest in taking advantage of cloud storage?
1) It's pretty inexpensive. Most services charge around $0.15/GB for data stored, and similar prices per GB of data transferred, and the pricing model is generally tiered to provide incentives for people to store more data to get better prices. This makes it far less expensive than traditional storage in many but not all cases
2) The worries of managing storage are relegated to your cloud storage provider. You can pretty much forget about replacing failed hard drives, or migrating data across systems when you run out of space, and many other things that make you want to pull out your hair
3) You can use as much as you want, and are only billed for what you use. Rather than dealing with large purchases up front - which is common since most people over-provision to account for their three-to-five year capacity needs - you get billed based on what you use, when you use it
4) Availability is "built-in". Most cloud storage service providers automatically replicate your data across their data centers, which are spread across the country or the world. Many claim that availability provided in this manner is lower cost than traditional storage system replication techniques while providing better up-time. Of course, there are other points of failure that need to be considered
Next time, we'll look at what the issues with cloud storage are in light of all of the benefits provided as described above. If you have anything you'd like to add to the list, or areas where you feel something needs clarification or an alternate viewpoint, please do leave a comment.