Patent ID: 8819208
Filing Date: 2014-08-26
Classification: G06F,H04L

Abstract:
1. A method for removing unused storage units, the method comprising: constructing, on a metadata server, a filter on at least a portion of block identifiers that identify storage units currently being referenced by client addresses, wherein at least one of the storage units is referenced by multiple client addresses, and wherein the metadata server stores information on which block identifiers are referenced by which client addresses; and transmitting the filter from the metadata server to a block server, wherein: the filter is used by the block server to identify which storage units being stored on the block server are in use and not in use based upon whether block identifiers that exist on the block server are present in the filter, wherein the block server stores information on where a storage unit is stored on the block server for a block identifier; a storage unit that is in use is determined when a block identifier for that storage unit is found in the filter; a storage unit that is not in use is determined when a block identifier for that storage unit is not found in the filter; and storage units not in use and associated block identifiers that are not present in the filter are deleted from the block server.