[PATCH v3 4/4] migration: Deprecate old compression method
Markus Armbruster
armbru at redhat.com
Thu Oct 12 10:06:22 UTC 2023
Juan Quintela <quintela at redhat.com> writes:
> Signed-off-by: Juan Quintela <quintela at redhat.com>
> Acked-by: Peter Xu <peterx at redhat.com>
> ---
> docs/about/deprecated.rst | 8 +++
> qapi/migration.json | 102 ++++++++++++++++++++++++--------------
> migration/options.c | 13 +++++
> 3 files changed, 86 insertions(+), 37 deletions(-)
>
> diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
> index e46f3df376..b92621996f 100644
> --- a/docs/about/deprecated.rst
> +++ b/docs/about/deprecated.rst
> @@ -441,3 +441,11 @@ Please see "QMP invocation for live storage migration with
> ``driver-mirror`` + NBD" in docs/interop/live-block-operations.rst for
> a detailed explanation.
>
> +old compression method (since 8.2)
> +''''''''''''''''''''''''''''''''''
> +
> +Compression method fails too much. Too many races. We are going to
> +remove it if nobody fixes it. For starters, migration-test
> +compression tests are disabled becase they fail randomly. If you need
> +compression, use multifd compression methods.
> +
> diff --git a/qapi/migration.json b/qapi/migration.json
> index bf6e1ac5b5..549306fa76 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -243,7 +243,9 @@
> #
> # @compression: migration compression statistics, only returned if
> # compression feature is on and status is 'active' or 'completed'
> -# (Since 3.1)
> +# This feature is unreliable and not tested. It is recommended to
> +# use multifd migration instead, which offers an alternative
> +# reliable and tested compression implementation. (Since 3.1)
> #
> # @socket-address: Only used for tcp, to know what the real port is
> # (Since 4.0)
> @@ -271,8 +273,11 @@
> #
> # Features:
> #
> -# @deprecated: @disk migration is deprecated. Use driver-mirror
> -# with NBD instead.
> +# @deprecated: @disk migration is deprecated. Use driver-mirror with
> +# NBD instead. @compression is unreliable and untested. It is
> +# recommended to use multifd migration, which offers an
> +# alternative compression implementation that is reliable and
> +# tested.
Again, single deprecation note under "Features:", please.
> #
> # Since: 0.14
> ##
> @@ -290,7 +295,7 @@
> '*blocked-reasons': ['str'],
> '*postcopy-blocktime': 'uint32',
> '*postcopy-vcpu-blocktime': ['uint32'],
> - '*compression': 'CompressionStats',
> + '*compression': { 'type': 'CompressionStats', 'features': ['deprecated'] },
> '*socket-address': ['SocketAddress'],
> '*dirty-limit-throttle-time-per-round': 'uint64',
> '*dirty-limit-ring-full-time': 'uint64'} }
> @@ -445,7 +450,8 @@
> # compress and xbzrle are both on, compress only takes effect in
> # the ram bulk stage, after that, it will be disabled and only
> # xbzrle takes effect, this can help to minimize migration
> -# traffic. The feature is disabled by default. (since 2.4 )
> +# traffic. The feature is disabled by default. Obsolete. Use
Some places call it "deprecated", others "obsolete". Best to always use
"deprecated".
More of the same below.
> +# multifd compression methods if needed. (since 2.4 )
> #
> # @events: generate events for each migration state change (since 2.4
> # )
[...]
Migration has grown way too many options. Thanks for pruning them back
some.
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