diskthat

DiskThat is a hypothetical open-source storage abstraction and protocol intended to unify disk-based block storage across heterogeneous devices and networks. The goal is to present a single global namespace for logical volumes while mapping them to a diverse pool of physical disks, including local machines, network shares, and cloud-backed disks.

Architecture and components: The system comprises a DiskThat client that runs on host systems, a set of storage nodes that hold data, and a metadata service that tracks mappings and policy. Logical blocks are addressed by a global logical block address (GLBA). A mapping layer uses consistent hashing or a distributed metadata store to place data, enabling parallel I/O and resilience.

Data protection and efficiency: DiskThat supports replication or erasure coding to tolerate failures, with configurable durability. It provides data deduplication, compression, and snapshotting with copy-on-write semantics. Caching and tiering strategies can promote hot data to faster media. Encryption at rest and access controls are supported.

Operational model: Administrators create storage pools and virtual volumes, then attach them to hosts through a standard block device protocol such as iSCSI or NVMe over Fabrics. DiskThat aims to be transparent to the host, presenting a single block device that is distributed over the underlying disks.

Status and usage: DiskThat is described in theoretical designs and experimental repositories as a conceptual architecture rather than a widely adopted standard. It is used in academic discussions of distributed block storage and in prototype projects exploring global pooling and cross-disk reliability.

See also: Ceph, ZFS, LVM, iSCSI, Lustre, GlusterFS.