One of the toughest challenges of storage management is to decide how much storage space is needed for a computer or application. If you allocate too little you may run out of space, too much and you waste valuable storage resources by tying it up to one computer.
Thin Provisioning is a fundamental capability of BeyondRAID, allowing you to allocate the right amount of storage for today, while allowing you to expand capacity by just adding a drive to the Drobo or replacing an existing drive with a larger one.
With Drobo, this expansion is nearly instant and occurs when a new or larger drive is inserted without any disruption in service. If you are running low on space, all you need is another hard drive to add to the Drobo. Adding more drives instantly increases usable storage capacity.
While 4- and 5-bay Drobos often contain one thinly provisioned 16 TB volume, 8- and 12-bay models allow for user-controlled volume creation. These volumes (or LUNs) are called Smart Volumes™ and they pull needed storage from a common pool (thin provisioning) and then return deleted blocks back to the common pool (thin reclamation), preventing free space from being tied up by any particular server.
Space allocation is automatically managed, which helps maximize storage resources. You can try this out for yourself. If you have a large file on a volume and then you delete it, you will see the free space of the Drobo grow, making that freed up space available to any other volume. Even enterprise-class arrays with thin provisioning do not return consumed storage back to a common pool at this granular of a level.
How do small and medium business (SMB) IT administrators effectively use solid state drives (SSDs) to accelerate their applications? They can't. Either the array is too expensive or the drives must be in their own pool and separate from the rest of the data. Data must be sent manually to the fast volume (SSD) or to the normal volume.
How can the IT administrator figure out what data is transactional in nature, that is, what data should be sent to the fast volume? To make things even more confusing and complicated, data can have mixed characteristics. But to get the most out of expensive SSDs, the solution must be intelligent and fully automatic—the data just needs to go to the right place automatically.
With the introduction of SSD support in the Drobo B1200i, SSDs provide a faster tier of storage for data that is transactional in nature, the type of data that benefits from the faster write and access speeds SSDs provide. (Automated Data-Aware Tiering will support SSDs in a software update targeted for Q1 2012).
As data enters the Drobo, if it is transactional, then the data is written to the faster tier of SSDs. Unlike enterprise arrays with auto-tiering, transactional data goes directly to SSDs, which ensures that BOTH writes AND reads are optimized.
Drobo's tiering functionality allows you to store any type of data on the Drobo and the data that can be optimized by SSDs is automatically optimized in flight. This means that all data—mixed data types from 10 or more VMs in a vSphere cluster, Exchange databases/datastores, backup data, or files on a file server—automatically goes to the right place.
Whether you have 8 HDDs and 2 SSDs or 9 HDDs and 3 SSDs, they will be utilized appropriately without any upfront setup. All the administrator has to do is put the drives in the Drobo.
After data is written to storage, data patterns often change. Sometimes a large amount of data is written to storage and not read for weeks or even months. On the other hand, it is not uncommon for a small amount of data to be written and accessed very frequently.
With Drobo's automated tiering, optimization of data doesn't stop when the data reaches a transactional or bulk storage tier. As the stored data is being read off the Drobo, the data is patterned and optimized in the background. Data that becomes hot will be moved to the transactional tier and visa versa.
If your Drobo contains only HDDs, but if your applications need even more performance, all you have to do is introduce SSDs to the Drobo. The SSDs then become the transactional tier and all of the HDDs are delegated to the bulk tier. The only administrative task is to insert new drives into the Drobo.
Note that Automated Data-Aware Tiering is currently available only for the Drobo B1200i. For additional information, read the Automated Data-Aware Tiering section of the Drobo Tech Whitepaper.