libvirt/tests/qemudomainsnapshotxml2xmlin/external_vm.xml

<domainsnapshot>
  <name>my snap name</name>
  <description>!@#$%^</description>
  <state>running</state>
  <memory snapshot='external' file='/dev/HostVG/GuestMemory'/>
  <parent>
    <name>earlier_snap</name>
  </parent>
</domainsnapshot>
snapshot: new XML for external system checkpoint Each <domainsnapshot> can now contain an optional <memory> element that describes how the VM state was handled, similar to disk snapshots. The new element will always appear in output; for back-compat, an input that lacks the element will assume 'no' or 'internal' according to the domain state. Along with this change, it is now possible to pass <disks> in the XML for an offline snapshot; this also needs to be wired up in a future patch, to make it possible to choose internal vs. external on a per-disk basis for each disk in an offline domain. At that point, using the --disk-only flag for an offline domain will be able to work. For some examples below, remember that qemu supports the following snapshot actions: qemu-img: offline external and internal disk savevm: online internal VM and disk migrate: online external VM transaction: online external disk ===== <domainsnapshot> <memory snapshot='no'/> ... </domainsnapshot> implies that there is no VM state saved (mandatory for offline and disk-only snapshots, not possible otherwise); using qemu-img for offline domains and transaction for online. ===== <domainsnapshot> <memory snapshot='internal'/> ... </domainsnapshot> state is saved inside one of the disks (as in qemu's 'savevm' system checkpoint implementation). If needed in the future, we can also add an attribute pointing out _which_ disk saved the internal state; maybe disk='vda'. ===== <domainsnapshot> <memory snapshot='external' file='/path/to/state'/> ... </domainsnapshot> This is not wired up yet, but future patches will allow this to control a combination of 'virsh save /path/to/state' plus disk snapshots from the same point in time. ===== So for 1.0.1 (and later, as needed), I plan to implement this table of combinations, with '' designating new code and '+' designating existing code reached through new combinations of xml and/or the existing DISK_ONLY flag: domain memory disk disk-only \| result ----------------------------------------- offline omit omit any \| memory=no disk=int, via qemu-img offline no omit any \|+memory=no disk=int, via qemu-img offline omit/no no any \| invalid combination (nothing to snapshot) offline omit/no int any \|+memory=no disk=int, via qemu-img offline omit/no ext any \|memory=no disk=ext, via qemu-img offline int/ext any any \| invalid combination (no memory to save) online omit omit off \| memory=int disk=int, via savevm online omit omit on \| memory=no disk=default, via transaction online omit no/ext off \| unsupported for now online omit no on \| invalid combination (nothing to snapshot) online omit ext on \| memory=no disk=ext, via transaction online omit int off \|+memory=int disk=int, via savevm online omit int on \| unsupported for now online no omit any \|+memory=no disk=default, via transaction online no no any \| invalid combination (nothing to snapshot) online no int any \| unsupported for now online no ext any \|+memory=no disk=ext, via transaction online int/ext any on \| invalid combination (disk-only vs. memory) online int omit off \|+memory=int disk=int, via savevm online int no/ext off \| unsupported for now online int int off \|+memory=int disk=int, via savevm online ext omit off \|memory=ext disk=default, via migrate+trans online ext no off \|+memory=ext disk=no, via migrate online ext int off \| unsupported for now online ext ext off \|memory=ext disk=ext, via migrate+transaction * docs/schemas/domainsnapshot.rng (memory): New RNG element. * docs/formatsnapshot.html.in: Document it. * src/conf/snapshot_conf.h (virDomainSnapshotDef): New fields. * src/conf/domain_conf.c (virDomainSnapshotDefFree) (virDomainSnapshotDefParseString, virDomainSnapshotDefFormat): Manage new fields. * tests/domainsnapshotxml2xmltest.c: New test. * tests/domainsnapshotxml2xmlin/.xml: Update existing tests. tests/domainsnapshotxml2xmlout/*.xml: Likewise. 2012-10-23 15:12:23 +00:00			`<domainsnapshot>`
			`<name>my snap name</name>`
			`<description>!@#$%^</description>`
			`<state>running</state>`
			`<memory snapshot='external' file='/dev/HostVG/GuestMemory'/>`
			`<parent>`
			`<name>earlier_snap</name>`
			`</parent>`
			`</domainsnapshot>`