[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH] doc: do not recommend -blockdev
From: |
Alex Bennée |
Subject: |
Re: [PATCH] doc: do not recommend -blockdev |
Date: |
Sat, 18 Mar 2023 12:32:13 +0000 |
User-agent: |
mu4e 1.9.22; emacs 29.0.60 |
Michael Tokarev <mjt@tls.msk.ru> writes:
> Currently, documentation recommends to use -blockdev instead of -drive.
> This is quite a bit misleading, because -blockdev is "too" low-level,
> requires good knowlege of how to construct block device stack, esp.
> in context of various qcow2 layers, and requires too explicit configuration.
> More, quite some constructs does not work with -blockdev, - for example
> this is -snapshot.
>
> Instead of "recommended" word, use another construct here.
Could we expand the images section:
https://qemu.readthedocs.io/en/latest/system/images.html
to give a better overview of when you should use -device/-blockdev vs -drive?
>
> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
> ---
> qemu-options.hx | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 59bdf67a2c..8fe31b465d 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1143,7 +1143,7 @@ have gone through several iterations as the feature set
> and complexity
> of the block layer have grown. Many online guides to QEMU often
> reference older and deprecated options, which can lead to confusion.
>
> -The recommended modern way to describe disks is to use a combination of
> +The low-level detailed way to describe disks is to use a combination of
> ``-device`` to specify the hardware device and ``-blockdev`` to
> describe the backend. The device defines what the guest sees and the
> backend describes how QEMU handles the data.
How about:
The most explicit way to describe disks is to use a combination of
``-device`` to specify the hardware device and ``-blockdev`` to
describe the backend. The device defines what the guest sees and the
backend describes how QEMU handles the data. The ``--drive`` option
combines the device and backend into a single command line options which
is useful in the majority of cases. Older options like ``-hda`` make a
bake in a lot of assumptions from the days when QEMU was emulating a
legacy PC, they are not recommended for modern configurations.
--
Alex Bennée
Virtualisation Tech Lead @ Linaro