Re: [Qemu-devel] [PATCH v0 1/7] migration: add background snapshot capability

[Eric Blake]

On 06/29/2018 03:03 AM, Denis Plotnikov wrote:
> The capability is used for the background vmstate saving
> using the migration infrastructure.
> Background vmstate saving means that the majority of vmstate
> (RAM) is saved in the background when VM's vCPUS are running.
> This helps to reduce the VM downtime on VM snapshotting.
>
> Signed-off-by: Denis Plotnikov <address@hidden>
> ---
>   migration/migration.c | 35 +++++++++++++++++++++++++++++++++++
>   migration/migration.h |  1 +
>   qapi/migration.json   |  6 +++++-
>   3 files changed, 41 insertions(+), 1 deletion(-)

> +++ b/qapi/migration.json
> @@ -352,12 +352,16 @@
>   #
>   # @x-multifd: Use more than one fd for migration (since 2.11)
>   #
> +# @background-snapshot: Using migration infrastructure makes VM snapshot
> +#         saving its RAM in background. This reduces  VM downtime. (since 2.12)

You've missed 2.12; the next release is 3.0 (and even then, we're fast 
coming up on soft freeze, so a maintainer must be willing to take this 
feature soon, or it will become 3.1 material).

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org