The question may relate to Host File System I/O size.
File systems can be configured for a minimum I/O extent size. This is the smallest indivisible I/O request given to the storage system. Typical values are 4 KB, 8 KB, 16 KB, or 64 KB. Applications performing I/O at sizes smaller than the file system¿s extent size cause unnecessary data movement or read-modify-write activity.
I note this explaination discusses minimum, and your question is in terms of maximum. The difference is in the Point-of-View, Host vs. Storage System.
If this is what is meant, the 'File System' section of EMC CLARiiON Best Practices for Performance and Availability, FLARE Revision 28.5 available on Powerlink has a longer discussion of the subject.