From: Peter Krempa Date: Mon, 13 Oct 2025 13:27:16 +0000 (+0200) Subject: docs: snapshot: Add a note that blockjobs ought to be avoided with 'manual' snapshots X-Git-Tag: v11.9.0-rc1~44 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1ebee849dbeaebda5e52206786f6dc5d8d1d4f45;p=thirdparty%2Flibvirt.git docs: snapshot: Add a note that blockjobs ought to be avoided with 'manual' snapshots Using a blockjob will reactivate the block nodes in qemu and thus e.g. qcow2 metadata such as bitmaps may become marked as dirty. Users of 'manual' snapshots ought to avoid those. Signed-off-by: Peter Krempa Reviewed-by: Michal Privoznik --- diff --git a/docs/formatsnapshot.rst b/docs/formatsnapshot.rst index b85194b6bb..98e3adc235 100644 --- a/docs/formatsnapshot.rst +++ b/docs/formatsnapshot.rst @@ -127,9 +127,12 @@ The top-level ``domainsnapshot`` element may contain the following elements: :since:`Since 8.2.0` the ``snapshot`` attribute supports the ``manual`` value which instructs the hypervisor to create the snapshot and keep a - synchronized state by pausing the VM which allows to snapshot disk + synchronized state by pausing the VM (and where supported deactivating + the storage backends of the hypervisor), which allows to snapshot disk storage from outside of the hypervisor if the storage provider supports - it. The caller is responsible for resuming a VM paused by requesting a + it. VM operations requiring the storage (e.g. blockjobs, migration) should + be avoided to ensure that the storage backends can stay deactivated. + The caller is responsible for resuming a VM paused by requesting a ``manual`` snapshot. When reverting such snapshot, the expectation is that the storage is configured in a way where the hypervisor will see the correct image state.