MULTIPLE NODE REPAIR USING HIGH RATE MINIMUM STORAGE REGENERATION ERASURE CODE

摘要

A distributed storage system can use a high rate MSR erasure code to repair multiple nodes when multiple node failures occur. An encoder constructs m r-ary trees to determine the symbol arrays for the parity nodes. These symbol arrays are used to generate the parity data according to parity definitions or parity equations. The m r-ary trees are also used to identify a set of recovery rows across helper nodes for repairing a systematic node. When failed systematic nodes correspond to different ones of the m r-ary trees, a decoder may select additional recovery rows. The decoder selects additional recovery rows when the parity definitions do not provide a sufficient number of independent linear equations to solve the unknown symbols of the failed nodes. The decoder can select recovery rows contiguous to the already identified recovery rows for access efficiency.