Get I/O Parameters ioctl

VxFS provides the VX_GET_IOPARAMETERS ioctl to get the recommended
I/O sizes to use on a file system. This ioctl can be used by the application to make decisions about the I/O sizes issued to VxFS for a file or file device. For more details on this ioctl, refer to the vxfsio(7) manual page. For a discussion on various I/O parfCameters, refer to Chapter 2 “VxFS Performance: Creating, Mounting, and Tuning File Systems” and the vxtunefs(1M) manual page.