Legato Systems Inc, of Palo Alto, California, has introduced the second release of its Prestoserve accelerator for Sun’s Network File System, a hardware and software product that is claimed to speed up the response time of heavily loaded servers. Prestoserve 2.0 supports Sun’s new top-end Sparc-based servers, the 390 and 490, which use Sun’s IPI disk controller. It also includes an improved window-based network performance monitor. The boost in performance comes from eliminating the common Network File System input-output bottleneck by buffering the server’s l file system state in fast non-volatile memory, and scheduling asynchronous writes to the server’s hard disks. According to Legato, the product is effective on large and complex Network File System networks and with diskless clients. System managers can add more client workstations to their existing file servers with no performance loss, and in some cases can eliminate the need for additional servers. Because of the synchronous nature inherent in Network File System writes, the Sun product could not previously take advantage of the Sun IPI disk controller, said Legato founder and principal engineer Joe Moran. By buffering Network File System writes, Prestoserve can use IPI disk controller features such as the ability to optimise seeks, improving write speeds on the Sun 490 by a factor of six or more, he said. Prestoserve includes a software tape, VMEbus board and documentation, and costs $8,000. The first release of Prestoserve was introduced in June 1989, and Legato claims that it has made 150 installations of it in the US.
