migration: improve documentation of postcopy-ram

This capability must have the same value on both source and destination,
otherwise migration fails (commit 875fcd013a "migration: incoming
postcopy advise sanity checks").

Let's write it down in various places where postcopy-ram is documented.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <151801810352.29167.4832480228518630626.stgit@bahia.lan>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
This commit is contained in:
Greg Kurz 2018-02-07 16:41:43 +01:00 committed by Dr. David Alan Gilbert
parent 96994fd1e4
commit c2eb7f213a
3 changed files with 10 additions and 7 deletions

View File

@ -387,8 +387,8 @@ doesn't finish in a given time the switch is made to postcopy.
Enabling postcopy Enabling postcopy
----------------- -----------------
To enable postcopy, issue this command on the monitor prior to the To enable postcopy, issue this command on the monitor (both source and
start of migration: destination) prior to the start of migration:
``migrate_set_capability postcopy-ram on`` ``migrate_set_capability postcopy-ram on``

View File

@ -1041,7 +1041,8 @@ ETEXI
.params = "", .params = "",
.help = "Followup to a migration command to switch the migration" .help = "Followup to a migration command to switch the migration"
" to postcopy mode. The postcopy-ram capability must " " 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, .cmd = hmp_migrate_start_postcopy,
}, },

View File

@ -327,8 +327,10 @@
# to speed up convergence of RAM migration. (since 1.6) # to speed up convergence of RAM migration. (since 1.6)
# #
# @postcopy-ram: Start executing on the migration target before all of RAM has # @postcopy-ram: Start executing on the migration target before all of RAM has
# been migrated, pulling the remaining pages along as needed. NOTE: If # been migrated, pulling the remaining pages along as needed. The
# the migration fails during postcopy the VM will fail. (since 2.6) # 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 # @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 # primary side will be migrated continuously to the VM on secondary
@ -742,8 +744,8 @@
# @migrate-start-postcopy: # @migrate-start-postcopy:
# #
# Followup to a migration command to switch the migration to postcopy mode. # Followup to a migration command to switch the migration to postcopy mode.
# The postcopy-ram capability must be set before the original migration # The postcopy-ram capability must be set on both source and destination
# command. # before the original migration command.
# #
# Since: 2.5 # Since: 2.5
# #