Dense tree volume metadata organization

摘要

The embodiments described herein are directed to an organization of metadata managed by a volume layer of a storage input/output (I/O) stack executing on one or more nodes of a cluster. The metadata managed by the volume layer, i.e., the volume metadata, is illustratively embodied as mappings from addresses, i.e., logical block addresses (LBAs), of a logical unit (LUN) accessible by a host to durable extent keys maintained by an extent store layer of the storage I/O stack. In an embodiment, the volume layer organizes the volume metadata as a mapping data structure, i.e., a dense tree metadata structure, which represents successive points in time to enable efficient access to the metadata.

主权项

1. A system comprising:
a central processing unit (CPU) of a node coupled to one or more storage devices; and a memory coupled to the CPU and configured to store a storage input/output (I/O) stack having a volume layer executable by the CPU, the volume layer configured to manage volume metadata embodied as mappings from offsets of a logical unit (LUN) to extent keys associated with storage locations on the one or more storage devices, the volume layer further configured to organize the volume metadata as a dense tree structure representing successive points in time to enable access to the volume metadata, the dense tree structure organized as multiple levels, the volume layer further configured to maintain a staging buffer for volume metadata entries inserted into a first level of the dense tree structure, wherein each level of the dense tree structure is maintained on the one or more storage devices as a packed array of the volume metadata entries, and wherein the volume metadata entries are stored as extents organized as metadata pages.