Architecture - OSS-on-DMU

Definitions
DMU - Data Management Unit, the core of ZFS filesystem implementing object storage, transactions, snapshots, pool management.

ZAP - an indexing subsystem of DMU, allows to operate on set of key->value pairs

FID - cluster-wide ID of any Lustre object, including objects on MDS'es and OSS'es

Implementation Constraints

 * 1) use ZAP for fid->dnode mapping
 * 2) use DMU's transactions
 * 3) single process to serve all DMU pools
 * 4) synchronous IO from libzpool to system (Solaris doesn't do AIO well)

OSS on DMU Architecture
The architecture of OSS includes few components: