Originally posted by: SystemAdmin
for aix
lsattr -El hdiskn will show queue_depth and max_transfer
lsattr -El fcs0 will show num_cmd_elems and max_xfer_size
queue_depth is the number of IOS that can be passed to disk in parallel.
queue can be checked whith command iostat -DRTl (look for serv qfull)
The maximum transfer size (max_transfer) sets the limit for the maximum size of an individual I/O to the disk. Although applications might make larger I/O requests, those requests are broken down into multiple max_transfer-sized requests before they are handed to the disk driver.
http://www.redbooks.ibm.com/abstracts/SG247821.html (chapter 3.4)