Benchmark for primitive I/O simulating HARD (durable) commit. This code is
intended to explore two elements:
(1) Pre-extending the journal file (so that FileChannel.force(false) usually
does not need to write any metadata.
(2) Performing I/O in fixed-length blocks so that to write a some bytes the
file system does not first need to read existing data from disk.
Parameters
align - smallest unit of I/O (default = 1) datapath - directory in which fake
journal file will be written (default = /tmp/persistit_test_data) buffersize
- emulated journal buffer size (default = 64M)