Become superuser.
Mount a file system with the forcedirectio mount option.
# mount -F ufs -o forcedirectio /dev/dsk/c0t3d0s7 /datab
Verify the mounted file system has forced direct I/O enabled.
# mount . . . /export/home on /dev/dsk/c0t3d0s7 read/write/setuid/forcedirectio ...