Thin provisioning is a technology of virtualization of data storages. It involves allocating space for data storage not immediately upon creating a logical disk, but as the need for this space arises.
The classic method of creating a logical disk requires setting a limit on the amount of data storage. For example, a system administrator, when installing an operating system on a personal computer, can divide a physical disk into several logical disks with a certain volume. This way, one of the logical disks, which is usually labeled “C”, is traditionally used to install the operating system, while the second one (for example, labeled “D” or “E”) stores all other data.
In all cases, administrators initially overallocate logical disk space so that the growing system has room to scale. For example, 200 GB may be allocated for the operating system on a personal computer, even though the system’s own files require barely a quarter of that amount. Nevertheless, over time the operating system libraries start to fill up with data due to installed applications.
The classical method of creating logical disks excludes the possibility of automatic volume scaling. In our example, if the operating system grows to 200 GB, it will only send a notification that the logical disk is full.
“Thin provisioning” data storage virtualization technology allows you to allocate virtual storage space on disk on demand. For example, if an application by default requires a data partition of 50 GB for its work, but after installation uses only 10 GB for its files, the technology will allow the application to “see” the required 50 GB on the disk, 40 GB of which will be virtual, i.e. will be filled only if the application’s libraries start to grow. This allows you not to overallocate space on the logical disk, but to add more space when the need arises.