Efficient updates in highly available distributed random access memory

With increased network speeds and throughputs, multicomputers (a system of computers connected by a high-speed network) have become an attractive alternative to store important data in their collective random access memory. Erasure codes provide space-optimal data redundancy to protect this type of storage from node unavailability. They have been used in LH*RS, the scalable high availability, distributed version of linear hashing. We present and evaluate a technique that uses the property of linear erasure correcting codes to make updates transactional and concurrent with recovery from one or more node availabilities without locks or two-phase commits. The technique significantly improves on previous work in update speed and also allows for serializable updates to a bucket that is in the process of being recovered