Patent ID: 7475207
Filing Date: 2009-01-06
Classification: G06F,H04L

Abstract:
1. A method of providing write order fidelity in a distributed set of data access nodes in a network, comprising the steps of: storing a write request to a first cache for an open delta, the first cache corresponding to a first node receiving the write request; transmitting a message, in response to a triggering event, to each node in the set of data access nodes to close the open delta; for each node having a write request for the open delta, completing any pending write requests for the open delta and closing the open delta; exchanging write request information among nodes so that each node is associated with a complete copy of the write request information for the closed delta; writing each complete copy to persistent storage; storing each complete copy of the closed delta to back-end storage for each node; and grouping front-end volumes into write-order fidelity (WOF) groups, each WOF group including at least one site across the network.