NetApp, Inc.
LATTICE LAYOUT OF REPLICATED DATA ACROSS DIFFERENT FAILURE DOMAINS

Abstract:

A technique organizes storage nodes of a cluster into failure domains logically organized vertically as protection domains of the cluster and stores replicas (i.e., one or more copies) of data (e.g., data block) on separate protection domains to ensure a replicated data layout such that a plurality of copies of a data block are resident at least on two or more different failure domains of nodes. An enhancement to the technique extends the layout of replicated data to include consideration of additional failure domains logically organized horizontally as replication zones of nodes storing the data. Each row (i.e., horizontal failure domain) is illustratively embodied as a "replication zone" that contains all replicas of the data block such that the blocks remain within the replication zone, i.e., no copies or replicas of data blocks are made between different replication zones. The enhanced technique organizes the replications zones orthogonal to the protection domains such that the replication zones are deployed (e.g., overlaid) across the plurality of protection domains in a manner that enhances the reliable and durable distribution of replicas of the data within nodes of the cluster. Thus, if an entire (vertical) protection domain of nodes fails or is lost, or if multiple nodes that are not in the same (horizontal) replication zone fail or are lost, then not all copies of the data are lost and the cluster is still operational and functional.