Distributed logging for transaction processin

This dissertation defends the thesis that recovery logs for transaction processing can be efficiently and reliably provided by a highly available network service. Recovery logs are a special implementation of stable storage that transaction processing systems use to record information essential to their operation. Recovery logs must be very reliable and have fast access. Typically, mirrored magnetic disks are dedicated to log storage in high performance transaction systems. Dedicated mirrored disks are an expensive resource for small processors like workstations or nodes in a non-shared memory multiprocessor. However, it is these types of processors that participate in many distributed programs and benefit from the availability of a general purposed distributed transaction facility. Distributed logging promotes reliable distributed computing by address the problem of the resources needed by the recovery log for a general purpose distributed transaction processing facility. The distributed logging thesis is defended by discussion of the design, implementation, and evaluation of distributed logging services. The design issues considered include the global representation of distributed logs, communication, security, log server data structures, log space management, and load assignment. A new distributed algorithm for replicating recovery logs and a new data structure for direct access to log records in append-only storage are presented. The dissertation explores the use of uninterruptible power supplies to implement low-latency non-volatile virtual memory disk buffers. The implementation and evaluation of the Distributed Log Facility for the Camelot Distributed Transaction Facility is described. The Camelot DLF uses the new distributed replication algorithm for representing distributed logs and uses uninterruptible power supplies to implement non-volatile virtual memory. Specially designed protocols are used for communication between clients and log servers in the Camelot DLF. The performance of the Camelot DLF is competitive with the Camelot local log implementation for a variety of benchmarks. The throughput capacity of log servers is reported.