2010/3/30 Jiri Denemark <jdenemar@redhat.com>:
Hi.
...
/* NOTE: struct _virDomainSnapshot is a private structure, ala * struct _virDomain. */ typedef struct _virDomainSnapshot virDomainSnapshot;
/* Take a snapshot of the current VM state. Throws an error if * the VM is not currently running */ virDomainSnapshotPtr virDomainSnapshotCreateXML(virDomainPtr domain, const char *xmlDesc, unsigned int flags);
This is probably a leftover from previous versions, but... why do we restrict this API only for running VMs?
Yep, if a domain it not running you'll just get a disk snapshot without a memory snapshot.
...
Possible issues: 1) I don't see a way to support "managed" save/restore and snapshotting with this API. I think we'll have to have a separate API for managed save/restore. 2) What is the semantic for deleting snapshots from a running domain? Virtualbox seems to not allow you to manipulate snapshots while the domain is running. Qemu does allow this, but it's currently unclear what the exact semantics are. VMware seems to allow manipulation of snapshots while the domain is running. 3) Do we need a snapshot UUID? Virtualbox allows you to have multiple snapshots with the same name, differentiated by UUID. Confusingly, they also have a "FindByName" method that returns the first depth-first search snapshot that matches a given name. For qemu, if you specify the same name twice it overwrites the previous one with the new one. I don't know what ESX does here.
Libvirt uses/generates UUIDs for almost everything (networks, vms, ...) so it might be more consistent to have UUID in snapshot as well.
ESX snapshots don't have a UUID, and there is no easy way to store an UUID-to-snapshot mapping. Matthias