In common usage scenarios, the physical disk space allocated for the volume is not immediately filled. For example, when a volume requests 1 TiB of physical disk space for data storage, it does not immediately fill the entire 1 TiB upon request. Instead, as business operations progress, the demand for data gradually increases over time. Therefore, the need for space typically grows incrementally. To improve storage utilization and reduce costs, ABS employs a thin provisioning policy. It allocates space in the Chunk only when data is actually written, using small data blocks (256 KiB) as the granularity.
Thin provisioning can be configured at the volume level and is enabled by default. After enabling thin provisioning, ABS can provide more logical storage space than the actual physical space. You can expand the storage space before your actual needs approach the physical space limit.
For volumes with thin provisioning enabled, ABS also supports TRIM/UNMAP space reclamation. When the used space on a volume is no longer in use (for example, when a file is deleted), the corresponding storage capacity can be released through space reclamation.
