rhevm - snapshots

RHEV-M Snapshots

Raz Tamir

OverviewIntroduction

Creation

Preview

Commit

Undo

Delete

Snapshots

Create Snapshot - Initial

Create Snapshot - Additional

Engine VDSM

CreateAllSnapshotsFromVmCommand

CreateSnapshotVDSCommand

CommandMultiAsyncTasks --> Task to VDSM Run and protect: createVolume

creating volume - lvcreate

qemu-img create -f qcow2 -F raw -b ...

GetImageInfoVDSCommand

Create Snapshots - Flow Of Events

Preview Snapshots

Engine VDSM

TryBackToAllSnapshotsOfVmCommand

TryBackToSnapshotCommand

CreateSnapshotVDSCommand

CommandMultiAsyncTasks --> Task to VDSM Run and protect: createVolume

creating volume - lvcreate

qemu-img create -f qcow2 -F raw -b .


Preview Snapshot - Flow Of Events

Commit Snapshot

Engine VDSM

RestoreAllSnapshotsCommand

DestroyImageVDSCommand

CommandMultiAsyncTasks --> Task to VDSM Run and protect: deleteVolume

update volume – lvchange (change tags)

delete LV – lvremove


Commit Snapshot - Flow Of Events

Undo Snapshot

Engine VDSM

RestoreAllSnapshotsCommand

DestroyImageVDSCommand

CommandMultiAsyncTasks --> Task to VDSM deleting volume – lvremove

update volumes – lvchange


Undo Snapshot - Flow Of Events

Delete Snapshots

The deletion of a snapshot does not necessarily cause the data in the snapshot to be deleted

The data from the deleted snapshot and the snapshot created after the deleted snapshot are merged into a single COW volume

No data has been removed, only the ability to restore a point in time in the life of the virtual machine hard disk image

Delete Snapshots

Engine VDSM

RemoveSnapshotSingleDiskCommand

MergeSnapshotsVDSCommand

CommandMultiAsyncTasks --> Task to VDSM MergeSnapshots

Creating volume - lvcreate (e.g. ..._MERGE)

qemu-img convert from to (-O fmt -f fmt )

deleting volume – lvremove

GetImageInfoVDSCommand update volumes – lvchange

Delete Snapshot - Flow Of Events

Questions?

Thank you!

rhevm - snapshots

Engineering