From: Greg Kurz <gr...@kaod.org> This capability must have the same value on both source and destination, otherwise migration fails (commit 875fcd013ab6 "migration: incoming postcopy advise sanity checks").
Let's write it down in various places where postcopy-ram is documented. Signed-off-by: Greg Kurz <gr...@kaod.org> Message-Id: <151801810352.29167.4832480228518630626.st...@bahia.lan> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com> Reviewed-by: Eric Blake <ebl...@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> --- docs/devel/migration.rst | 4 ++-- hmp-commands.hx | 3 ++- qapi/migration.json | 10 ++++++---- 3 files changed, 10 insertions(+), 7 deletions(-) diff --git a/docs/devel/migration.rst b/docs/devel/migration.rst index bf97080dac..9d1b7657f0 100644 --- a/docs/devel/migration.rst +++ b/docs/devel/migration.rst @@ -387,8 +387,8 @@ doesn't finish in a given time the switch is made to postcopy. Enabling postcopy ----------------- -To enable postcopy, issue this command on the monitor prior to the -start of migration: +To enable postcopy, issue this command on the monitor (both source and +destination) prior to the start of migration: ``migrate_set_capability postcopy-ram on`` diff --git a/hmp-commands.hx b/hmp-commands.hx index 15620c94d3..d26eb4119b 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -1041,7 +1041,8 @@ ETEXI .params = "", .help = "Followup to a migration command to switch the migration" " to postcopy mode. The postcopy-ram capability must " - "be set before the original migration command.", + "be set on both source and destination before the " + "original migration command .", .cmd = hmp_migrate_start_postcopy, }, diff --git a/qapi/migration.json b/qapi/migration.json index 4cd3d13158..7f465a1902 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -327,8 +327,10 @@ # to speed up convergence of RAM migration. (since 1.6) # # @postcopy-ram: Start executing on the migration target before all of RAM has -# been migrated, pulling the remaining pages along as needed. NOTE: If -# the migration fails during postcopy the VM will fail. (since 2.6) +# been migrated, pulling the remaining pages along as needed. The +# capacity must have the same setting on both source and target +# or migration will not even start. NOTE: If the migration fails during +# postcopy the VM will fail. (since 2.6) # # @x-colo: If enabled, migration will never end, and the state of the VM on the # primary side will be migrated continuously to the VM on secondary @@ -742,8 +744,8 @@ # @migrate-start-postcopy: # # Followup to a migration command to switch the migration to postcopy mode. -# The postcopy-ram capability must be set before the original migration -# command. +# The postcopy-ram capability must be set on both source and destination +# before the original migration command. # # Since: 2.5 # -- 2.14.3