thin volume
also: thin provisioning, thin logical volume, LVM thin volume
A logical volume that doesn't pre-allocate all its storage space upfront, but allocates disk blocks dynamically as data is written to it. This allows multiple thin volumes to share a larger pool of physical storage, enabling over-provisioning.
A thin volume is a logical volume in LVM (Logical Volume Manager) that reports a larger capacity than the physical space it initially consumes. Rather than allocating all requested storage immediately, it allocates blocks on-demand as applications write data.
This is useful for virtual machines and containers where you may want to offer users a large virtual disk (e.g., 100GB) but only consume physical storage as needed. For example, you could create ten 100GB thin volumes from a 500GB thin pool, knowing that not all will be fully populated simultaneously.
Thin provisioning comes with a trade-off: if the underlying pool runs out of free space, writes to thin volumes will fail. Tools like lvs and lvdisplay help monitor thin volume usage and pool capacity to prevent this scenario.