VDT - Visual Disk Test : performs I/O tests on files, partitions, and/or disks with visual feedback/follow-up, offering flexible test area selection by size, location, percent, or combinations thereof, plus test duration control by time or size.
The fs_mark benchmark tests synchronous write workloads. It can vary the number of files, directory depth, etc. It has detailed timings for reads, writes, unlinks and fsyncs that make it good for simulating mail servers and other setups.