Using DTrace to secure a more comprehensive view of IO sizes and alignments than is possible with iostat, for example, is the subject of Lisa Noordergraaf's blog "IO Sizes and Alignments with DTrace." The problem with iostat, she writes, is that while that utility does show the total number of reads and writes, it does not provide the necessary detail about individual sizes and alignments (start addresses) of the IOs as DTrace can.
(Get More Information . .)