Getting the I/O size

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.

See the vxtunefs(1M) and vxfsio(7) manual pages.

See Tuning I/O.