Patent attributes
A system maintains a consistency database that maintains a status (current, down, stale) for copies of logical storage volumes stored on storage nodes. As failures are detected, the consistency database is updated. Copies are synchronized with one another using information in the consistency database. Write operations on a primary node for a slice of a logical storage node are assigned a virtual block address (VBA) that is mapped to a logical block address (LBA) within the slice. Consistency of the VBAs of the primary node and that of a secondary node is evaluated and used to detect currency. VBA holes are detected and corresponding write commands resent to maintain currency. Physical segments on the primary node are assigned virtual segment identifiers (VSID) that are maintained consistent with VSIDs on clone nodes so that they can be used for garbage collection and synchronization.
