https://bugzilla.redhat.com/show_bug.cgi?id=1698863 reports that while "qemu-img create -f raw" supports the "preallocation" option, it is not listed under "-o help".
It turns out it is, but only if you specify a target filename. Users may not realize this, but a note should help. Max Reitz (2): iotests: Perform the correct test in 082 qemu-img: Make create hint at protocol options qemu-img.c | 13 ++++++++++++- tests/qemu-iotests/082 | 5 ++++- tests/qemu-iotests/082.out | 25 ++++++++++++++++++------- 3 files changed, 34 insertions(+), 9 deletions(-) -- 2.20.1