On 11/01/2012 10:22 AM, Peter Krempa wrote:
The default behavior while creating external checkpoints is to pause the guest while the memory state is captured. We want the users to sacrifice space saving for creating the memory save image while the guest is live to minimize downtime.
This patch adds a flag that causes the guest not to be paused before taking the snapshot. *include/libvirt/libvirt.h.in: - add new paused reason: VIR_DOMAIN_PAUSED_SNAPSHOT - add new flag for taking snapshot: VIR_DOMAIN_SNAPSHOT_CREATE_LIVE *tools/virsh-domain-monitor.c: - add string representation for VIR_DOMAIN_PAUSED_SNAPSHOT *tools/virsh-snapshot.c: - add support for VIR_DOMAIN_SNAPSHOT_CREATE_LIVE *tools/virsh.pod: - add docs for --live option added to use VIR_DOMAIN_SNAPSHOT_CREATE_LIVE flag ---
+++ b/src/libvirt.c @@ -17770,6 +17770,12 @@ virDomainSnapshotGetConnect(virDomainSnapshotPtr snapshot) * running after the snapshot. This flag is invalid on transient domains, * and is incompatible with VIR_DOMAIN_SNAPSHOT_CREATE_REDEFINE. * + * If @flags includes VIR_DOMAIN_SNAPSHOT_CREATE_LIVE, then the domain + * is not paused while creating the snapshot. This increases the size + * of the memory dump file, but reduces downtime of the guest while + * taking the snapshot. (Note: this feature works only with external + * checkpoints)
It is entirely feasible that we could do an internal snapshot without pausing the guest, if future qemu gave us support; so our documentation should be couched in terms of possible restrictions, not permanent restrictions. s/(Note: this feature works only with external checkpoints)/Some hypervisors only support this flag during external checkpoints./ The virsh.pod wording is fine. ACK with that change. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org