Storage experts have been trying to develop new ways of heading off unchecked file growth for years. Thin provisioning is one such solution, and I will explain the advantage of thin provisioning with cloud storage in a moment, but first let’s discuss what this concept actually means. Thin provisioning is all about providing access to more data or more storage than actually resides in a given device. If you look at it from an IT perspective, thin provisioning means you only have to buy the storage you need when you need it. You don’t have to purchase a whole new data center and gradually fill it up.
Now, if you attempt this without thin provisioning you can run into serious trouble. When the time comes, you may not have the storage on hand to grow. The storage may not be that easy to expand. Block-based volumes, for example, aren’t easily resized without affecting the file systems or applications that live on top of them. Granted, thin provisioning still means you have to add that storage capacity. The difference is that you don’t have to do it far in advance of the need.
Thin provisioning came to the consumer market in the form of the Data Robotics Drobo box. Users would start out with drives that claimed to have 2TB of space, when in reality only a percentage of that was available. Companies have also been implementing thin provisioning for years in both block-based systems and file systems. With a block-based system, you may claim to have a PB of storage while you only have 500TB dedicated. As the space is used up, the administrator receives alerts to allocate additional storage (more disks, more volumes, more enclosures, etc.). This way, the administrator avoids the pain of resizing the file systems or volumes behind the applications. Instead, the administrator creates a very large volume once, thin provisions it so there’s no need to buy all the actual storage right away, and then avoids the migration and growth problems later on.
If you are familiar with virtual environments, you may have also been exposed to thin provisioning with sparse (or thin) volumes. The volume reports itself as a certain size to the virtual client, but doesn't take up the actual space on disk until the client uses the space. So, even if you have only 100GB of available disk space, you can create ten virtual Windows 7 clients with a 30GB thin provisioned hard drive for each in your virtual environment. This works and works well as long as the actual 100GB is not used up as your clients grow their data use. One of the advantages is that you do not have to plan in advance which client will use more space and when.
Recently I wrote at length about caching, and caching the cloud in particular, and there are some similarities here. Caching is a form of thin provisioning in that the data is not 100% resident at any given point in time. It’s made to look as if it’s present. The appliance reports that it has all the data. It appears to continually have available capacity. But the caching algorithms are working behind the scenes to access the actual storage and make room for new data.
The advantage of thin provisioning with cloud storage is that there’s always more space available. You can always get more, and you don’t need to worry about oversubscription, purchasing cycles, and all the problems you can run into when thin provisioning breaks down. This concept is one of the core benefits of our cloud gateway technology, the Nasuni Filer. We’ve taken this marriage of thin provisioning and cloud storage and combined it with a file system that is built to live on top of cloud storage. Our users enjoy an unlimited file system that feels local, yet they pay as they go, expanding their capacity in line with their needs.
You can download a free trial of the Nasuni Filer today.