I/O-oriented applications on a software distributed-shared memory system
Parker, Timothy Paul
Cox, Alan L.
Master of Science
This thesis evaluates the use of a software distributed shared memory system, Treadmarks, as a platform for supporting an I/O-intensive application, specifically the database Postgres. Software distributed shared memory (DSM) systems allow applications to run on cheap and powerful networks of workstations without the complexity of explicit message-passing. Such systems are usually used for computationally-intensive scientific applications. I/O-intensive applications have significantly different characteristics. Despite this, Postgres needed only minimal changes to run on Treadmarks. This is partially because we wrote emulation layers for many APIs Postgres already used. We created additional support pieces for Treadmarks to handle the problems that arose because of the different application characteristics. These were divided into three areas. Some issues were related to usage of forms of communication other than shared memory, some to Treadmarks, and some to the UNIX API. We discuss and evaluate solutions to these problems.