From 61fb654db8dd6e0c2b63645f2250e671058fee8a Mon Sep 17 00:00:00 2001 From: Wei Zhou Date: Thu, 22 Oct 2026 17:33:29 +0200 Subject: [PATCH] Document KVM volume live migration on Ceph RBD and between RBD and file-based pools --- source/adminguide/storage.rst | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/source/adminguide/storage.rst b/source/adminguide/storage.rst index d0283b234c..3ba02f2479 100644 --- a/source/adminguide/storage.rst +++ b/source/adminguide/storage.rst @@ -893,17 +893,30 @@ Migrating an Instance Volume to a New Storage Pool (XenServer, VMware) You can live migrate an Instance's volumes from one storage pool to another, without stopping the Instance first. -(KVM) KVM does not support volume live migration due to the limited possibility -to refresh VM XML domain. Therefore, to live migrate a volume between storage pools, -one must migrate the VM to a different host as well to force the VM XML domain update. -Use 'migrateVirtualMachineWithVolumes' instead or stop the Instance and then migrate -the volume. +(KVM) A volume of a running Instance can be live migrated, without stopping or moving +the Instance, between: + +- two Ceph RBD primary storage pools; +- a Ceph RBD pool and an NFS, SharedMountPoint or local (host-scoped) pool, in both directions. + +For a local pool, the pool must be the one of the host the Instance is running on, as the copy +runs on that host. The whole disk is copied, hence a volume created from a template does not +depend on the backing file of the source pool afterwards, and the source volume is removed once +the migration is completed. Encrypted volumes can be migrated between RBD and NFS pools, both +online and offline. + +For any other pair of pools, such as two NFS pools, KVM does not support volume live migration +due to the limited possibility to refresh VM XML domain. Therefore, one must migrate the +Instance to a different host as well to force the VM XML domain update, using +'migrateVirtualMachineWithVolumes', or stop the Instance and then migrate the volume. +A volume which is not attached to a running Instance can be migrated between any of these pools. #. Log in to the CloudStack UI as a user or admin. #. In the left navigation bar, click Instances, and click the Instance name. -#. (KVM only) Stop the Instance. +#. (KVM only) Stop the Instance, unless the volume is migrated live between the + storage pools listed above. #. Click the Migrate button |Migrateinstance.png| and choose the destination from the dropdown list. @@ -916,7 +929,7 @@ the volume. #. Watch for the volume status to change to Migrating, then back to Running (or Stopped, in the case of KVM). This can take some time. -#. (KVM only) Restart the Instance. +#. (KVM only) Restart the Instance, if it was stopped. .. note:: In case of KVM and PowerFlex/ScaleIO storage, live migration of