Implementation of a Reliable Remote Memory Pager

Traditional operating systems use magnetic disks as paging devices even though the cost of a disk transfer measured in processor cycles contin ues to increase In this paper we explore the use of remote main memory for paging We describe the de sign implementation and evaluation of a pager that uses main memory of remote workstations as a faster than disk paging device and provides reliability in case of single workstation failures Our pager has been implemented as a block de vice driver linked to the DEC OSF operating system without any modi cations to the kernel code Using several test applications we measure the performance of remote memory paging over an Ethernet interconnection network and nd it to be faster than traditional disk paging We eval uate the performance of various reliability policies and prove their feasibility even over low bandwidth networks like Ethernet We conclude that the bene ts of reliable re mote memory paging in workstation clusters are signi cant today and will probably increase in the