Merge pull request #92182 from Vaishali-gif-rh/CNV-47262

CNV#47262

Author: kcarmichael08

modules/virt-optimizing-clone-performance-at-scale-in-openshift-data-foundation.adoc

@@ -0,0 +1,37 @@
+// Module included in the following assemblies:
+//
+// * virt/virtual_machines/creating_vms_custom/virt-creating-vms-by-cloning-pvcs.adoc
+
+:_mod-docs-content-type: PROCEDURE
+[id="virt-optimizing-clone-performance-at-scale-in-openshift-data-foundation_{context}"]
+= Optimizing clone Performance at scale in {rh-storage}
+
+When you use {rh-storage}, the storage profile configures the default cloning strategy as `csi-clone`. However, this method has limitations, as shown in the following link. After a certain number of clones are created from a persistent volume claim (PVC), a background flattening process begins, which can significantly reduce clone creation performance at scale.
+
+To improve performance when creating hundreds of clones from a single source PVC, use the `VolumeSnapshot` cloning method instead of the default `csi-clone` strategy.
+
+.Procedure
+Create a `VolumeSnapshot` custom resource (CR) of the source image by using the following content:
+[source,yaml]
+----
+apiVersion: snapshot.storage.k8s.io/v1
+kind: VolumeSnapshot
+metadata: 
+  name: golden-volumesnapshot
+  namespace: golden-ns
+spec:
+  volumeSnapshotClassName: ocs-storagecluster-rbdplugin-snapclass
+  source:
+    persistentVolumeClaimName: golden-snap-source
+----
+
+. Add the  `spec.source.snapshot` stanza to reference the `VolumeSnapshot` as the source for the `DataVolume clone`:
+
+[source,yaml]
+----
+spec:
+  source:
+    snapshot:
+      namespace: golden-ns
+      name: golden-volumesnapshot
+----

virt/creating_vms_advanced/creating_vms_cli/virt-creating-vms-by-cloning-pvcs.adoc

@@ -31,6 +31,14 @@ This method creates a data volume whose lifecycle is independent of the original
 +
 This method creates a data volume whose lifecycle is dependent on the original VM. Deleting the original VM deletes the cloned data volume and its associated PVC.
 
+include::modules/virt-optimizing-clone-performance-at-scale-in-openshift-data-foundation.adoc[leveloffset=+2]
+
+[role="_additional-resources"]
+.Additional resources
+* xref:../../../virt/storage/virt-configuring-storage-profile.adoc#virt-customizing-storage-profile-default-cloning-strategy_virt-configuring-storage-profile[Setting a default cloning strategy using a storage profile]
+* link:https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.18/html/managing_and_allocating_storage_resources/volume-cloning_rhodf#volume-cloning_rhodf[Volume cloning]
+* link:https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html/storage/using-container-storage-interface-csi#persistent-storage-csi-snapshots[CSI volume snapshots]
+
 include::modules/virt-cloning-pvc-to-dv-cli.adoc[leveloffset=+2]
 
 include::modules/virt-creating-vm-cloned-pvc-data-volume-template.adoc[leveloffset=+2]