Why PVC is also getting created when using copyMethod Snapshot?

[winkrs]

From what I understand, when a copyMethod Snapshot is being used and the destinationPVC is not specified then a snapshot of the source PVC will be created. Then, we can create a new PVC and uses the volume populator to reference the volume snapshot as the data source. However, what I do not understand is that along with the volumeSnapshot, a PVC is also created in the destination. Can anyone explain why is it this way?

[tesshuflower]

@winkrs The destination PVC still needs to be created as this is where the data is copied to during the sync operation on the replicationdestination. Note that if we're talking about the replicationdestination, then the snapshot is actually a copy of the destination PVC after the sync operation has completed.

The source PVC would only be snapshotted at the replicationsource side.

Steps on the destination:

• check if destinationPVC exists, or if not specified, create a destination PVC to write data to
• perform the sync operation - the destination mover pod will write to the destination PVC
• Perform a snapshot of this destination PVC

At this point if you had a replication destination that is doing syncs on a schedule, it's desirable to keep the destination PVC around, as it will already have a copy of the data, and then only the delta can be sent (a good example for where this is useful is rsync).

If you delete a replicationdestination then volsync will clean up the temporary destination pvc if it had originally created it. If you're using the volumepopulator and have provisioned a pvc pointing to that replicationdestination - once that pvc is provisioned you are free to delete the replicationdestination associated with it.

[winkrs]

okay, its making sense now. Thank you for clearing my doubt.