IP storage and the CPU consumption myth

Abstract

Addresses a key issue that arises when attaching storage devices directly to IP networks: the perceived need for hardware acceleration of the TCP/IP networking stack. While many implicitly assume that acceleration is required, the evidence shows that this conclusion is not well-founded. In the past, network accelerators have had mixed success, and the current economic justification for hardware acceleration is poor, given the low cost of host CPU cycles. The I/O load for many applications is dominated by disk latency, not transfer rate, and hardware protocol accelerators have little effect on the I/O performance in these environments. Application benchmarks were run on an IP storage subsystem to measure performance and CPU utilization on e-mail, database, file serving and backup applications. The results show that good performance can be obtained without protocol acceleration.