Patent ID: 7325109
Filing Date: 2008-01-29
Classification: G06F,H04L,Y10S

Abstract:
1. A method for mirroring data on a first storage server and a second storage server, the method comprising: queuing write commands in a temporary storage of the first storage server between consistency points, wherein each consistency point is an event characterized by executing the write commands queued in the temporary storage to write data corresponding to a file system of the first storage server to a local set of mass storage devices coupled to the first storage server; in response to initiation of each consistency point, concurrently sending the write commands queued in the temporary storage from the first storage server to the local set of mass storage devices and to a remote set of mass storage devices coupled to the second storage server, wherein the memory blocks of the local and remote sets of mass storage devices include address blocks that each store a pointer to another block in use by the file system, and data blocks that store data for the file system; updating memory blocks of the local and remote sets of mass storage devices based on the write commands; and at an end of each consistency point, constructing a representation to reference each memory block of the local set of mass storage devices that is in use to represent the file system, the representation being in the form of a sub-tree structure that includes nodes that represent one or more of the address blocks and one or more of the data blocks, the sub-tree structure being rooted in a root node that includes a pointer to the sub-tree structure; and sending only said root node from the first storage server to the second storage server, said root node comprising information to allow reconstruction of the entire representation by the second storage server.