docs: Add snapshot-revert qemu managedsave force

Add documentation for additional reason why snapshot-revert might need
to be forced. This explains why restoring an inactive snapshot while
there is managed saved state is refused by default.

Signed-off-by: Michael Weiser <michael.weiser@gmx.de>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
This commit is contained in:
Michael Weiser 2020-01-03 19:43:25 +01:00 committed by Michal Privoznik
parent 29773f2a75
commit 66ec00ab3e

View File

@ -6970,7 +6970,7 @@ no vm state leaves the domain in an inactive state. Passing either the
transient domains cannot be inactive, it is required to use one of these
flags when reverting to a disk snapshot of a transient domain.
There are two cases where a snapshot revert involves extra risk, which
There are a number of cases where a snapshot revert involves extra risk, which
requires the use of *--force* to proceed:
* One is the case of a snapshot that lacks full domain information for
@ -6980,7 +6980,7 @@ requires the use of *--force* to proceed:
libvirt that the snapshot is compatible with the current configuration
(and if it is not, the domain will likely fail to run).
* The other is the case of reverting from a running domain to an active
* Another is the case of reverting from a running domain to an active
state where a new hypervisor has to be created rather than reusing the
existing hypervisor, because it implies drawbacks such as breaking any
existing VNC or Spice connections; this condition happens with an active
@ -6988,6 +6988,13 @@ requires the use of *--force* to proceed:
an inactive snapshot that is combined with the *--start* or *--pause*
flag.
* Also, libvirt will refuse to restore snapshots of inactive QEMU domains
while there is managed saved state. This is because those snapshots do not
contain memory state and will therefore not replace the existing memory
state. This ends up switching a disk underneath a running system and will
likely cause extensive filesystem corruption or crashes due to swap content
mismatches when run.
snapshot-delete
---------------