PostMark is the benchmark used in the NetApp Technical Report TR3022,
"PostMark: A New File System Benchmark".  The paper fully explains how
to use this tool.

From the paper's Abstract:
	Existing file system benchmarks are deficient in portraying
	performance in the ephemeral small-file regime used by Internet
	software, especially:
		* electronic mail
		* netnews
		* web-based commerce

PostMark is a new benchmark to measure performance for this class of
application.