VMware, Inc.
ENHANCING EFFICIENCY OF SEGMENT CLEANING FOR A LOG-STRUCTURED FILE SYSTEM

Abstract:

The efficiency of segment cleaning for a log-structured file system (LFS) is enhanced at least by storing additional information in a segment usage table (SUT). Live blocks (representing portions of stored objects) in an LFS are determined based at least on the SUT. Chunk identifiers associated with the live blocks are read. The live blocks are coalesced at least by writing at least a portion of the live blocks into at least one new segment. A blind update of at least a portion of the chunk identifiers in a chunk map is performed to indicate the new segment. The blind update includes writing to the chunk map without reading from the chunk map. In some examples, the objects comprise virtual machine disks (VMDKs) and the SUT changes between a list format and a bitmap format, to minimize size.