SNAPSHOTS AND CLONES OF VOLUMES IN A STORAGE SYSTEM

摘要

In one embodiment, snapshots and/or clones of storage objects are created and managed by a volume layer of a storage input/output (I/O) stack executing on one or more nodes of a cluster. Illustratively, the snapshots and clones may be represented as independent volumes, and embodied as respective read-only copies (snapshots) and read-write copies (clones) of a parent volume. Volume metadata is illustratively organized as one or more multi-level dense tree metadata structures, wherein each level of the dense tree metadata structure (dense tree) includes volume metadata entries for storing the metadata. Each snapshot/clone may be derived from a dense tree of the parent volume (parent dense tree). Portions of the parent dense tree may be shared with the snapshot/clone.

主权项

1. A method comprising:
receiving a first write request directed towards a logical unit (LUN), the first write request having a first data, a LUN identifier (ID), a logical block address (LBA) and a length representing an address range of the LUN, the LUN ID, LBA and length mapped to a volume associated with the LUN, the first write request processed at a storage system having a memory; associating a first key with the first data; storing the first key in a first data entry of a metadata structure having a plurality of levels, the first data entry representing the volume, the volume including a superblock, the superblock having a first reference to the metadata structure; producing a copy of the volume by creating a copy of an in-core portion of the metadata structure that includes at least a top level of the metadata structure and a copy of the super block, and, at least initially, sharing among the volume and the copy of the volume a remaining portion of the metadata structure that includes at least one more lower levels of the metadata structure residing on a storage array of storage devices; and storing the first data entry, the superblock and the copy of the superblock in the storage array.