Re: More detail please Mr Kaminario
Agreed. In my experience, the average block size is usually strongly bimodal -- you may get a lot of I/O at, say, 4-8KB, and then you may get a lot of I/O at, say, 32-40KB, with relatively little I/O of other sizes.
Looking at these and saying "Well, the average is somewhere in the middle of 8 and 40" is, in my mind, not accurate.