SmartTier matches data storage with data usage requirements. After data matching, the data can then be relocated based upon data usage and other requirements determined by the storage or database administrator (DBA).
As more and more data is retained over a period of time, eventually, some of that data is needed less frequently. The data that is needed less frequently still requires a large amount of disk space. SmartTier enables the database administrator to manage data so that less frequently used data can be moved to slower, less expensive disks. This also permits the frequently accessed data to be stored on faster disks for quicker retrieval.
Tiered storage is the assignment of different types of data to different storage types to improve performance and reduce costs. With SmartTier, storage classes are used to designate which disks make up a particular tier. There are two common ways of defining storage classes:
Performance, or storage, cost class: The most-used class consists of fast, expensive disks. When data is no longer needed on a regular basis, the data can be moved to a different class that is made up of slower, less expensive disks.
For example, a database is usually made up of data, an index, and logs. The data could be set up with a three-way mirror because data is critical. The index could be set up with a two-way mirror because the index is important, but can be recreated. The redo and archive logs are not required on a daily basis but are vital to database recovery and should also be mirrored.
SmartTier policies control initial file location and the circumstances under which existing files are relocated. These policies cause the files to which they apply to be created and extended on specific subsets of a file systems's volume set, known as placement classes. The files are relocated to volumes in other placement classes when they meet specified naming, timing, access rate, and storage capacity-related conditions.
In addition to preset policies, you can manually move files to faster or slower storage with SmartTier, when necessary. You can also run reports that list active policies, display file activity, display volume usage, or show file statistics.