I discovered the following command in this whitepaper:
WinSat disk -read -ran -ransize 4096 -drive c
Is it reliable to use against a SAN, or iSCSI drive? I would like to compare the output of various hosts.
SQLIO is great for performing these kinds of tests. Don't let the name fool you, it is not Sql Server specific. You can use it to test various combinations of Reads vs Writes, Random vs Sequential IO. It supports arbitrary block sizes, numbers of threads and number of outstanding IOs across files of arbitrary size, so it is applicable to many different workload types.
It will give you IOPs, total throughput, and a histogram of latency statistics. It's the best tool I've found to generate substantial IO load before going to production with new HW.