Logical Unit Management using Differencing

摘要

A storage system may manage a logical unit using a differencing mechanism that captures changes to a base version of the logical unit. The logical unit may be presented to an operating system as a single storage device, while the logical unit may actually be provided by several storage devices that operate in conjunction with each other. In some cases, a single base version of the logical unit may be used to simultaneously provide multiple logical units, each of the logical units having a separate and independent differencing portion. In one such embodiment, a common base extent may contain read only versions of file blocks while each logical unit may contain independent differencing extents that contain changes to the base extent.

主权项

1. A method performed on a computer processor, said method comprising:
receiving a first logical unit definition; configuring a first plurality of storage devices as a first logical unit in compliance with said first logical unit definition; creating a base image and a first differencing image for said first logical unit; presenting said first logical unit to a first operating system; receiving a first write request from said first operating system, said write request comprising a changed first block; and storing said changed first block in said first differencing image and updating first logical unit metadata, said first logical unit metadata identifying said first block as being modified in said first logical unit.