On 2024-04-25 14:51, lacsaP Patatetom wrote:
> Le jeu. 25 avr. 2024 à 11:30, Peter Maydell <peter.maydell@linaro.org
> <mailto:peter.maydell@linaro.org>> a écrit :
>
> On Thu, 25 Apr 2024 at 09:55, lacsaP Patatetom
> <patatetom@gmail.com <mailto:patatetom@gmail.com>> wrote:
> >
> > hi,
> >
> > when using `qemu-img create`, why do I have to specify the
> format of the base image ?
> > can't `qemu-img` detect it itself ?
>
> Image format detection isn't 100% reliable. Notably, a 'raw'
> format image could in theory look like any of the other
> image types if it happens to start with the right kind of data.
>
> thanks
> -- PMM
>
>
> OK for the raw format, which can be anything, but not for the qcow2
> format, which is standardized (header).
> in the absence of details, `qemu-img` could use the qcow2 format by
> default ?
>
> qemu-img create [-b base [-F (qcow2*|raw)]] [-f (qcow2*|raw)] image [size]
But it cannot safely tell if the base file (usually a raw image or raw
physical
disk partition) is qcow2 or araw file that just happens to begin with
the magic
bytes that represent qcow2.
Enjoy
Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S. https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark. Direct +45 31 13 16 10
This public discussion message is non-binding and may contain errors.
WiseMo - Remote Service Management for PCs, Phones and Embedded
I understand the problem of the wrong format and that `qemu-img` therefore requires the image format to be specified.
however, for the base image, it's the underlying layer that shouldn't be and won't be altered by the use of the newly created image, given that the latter is based on it.
should it therefore be possible to specify the format of the base image as an option ?
regards, lacsaP.