Merge pull request #57960 from ousleyp/cnv-25138

CNV-25138: storage volume requirements/removing assembly

Author: ousleyp

_topic_maps/_topic_map.yml

@@ -3658,8 +3658,6 @@ Topics:
   - Name: Virtual machine disks
     Dir: virtual_disks
     Topics:
-    - Name: Features for storage
-      File: virt-features-for-storage
     - Name: Configuring local storage for virtual machines
       File: virt-configuring-local-storage-for-vms
     - Name: Creating data volumes

modules/virt-about-storage-volumes-for-vm-disks.adoc

@@ -0,0 +1,29 @@
+// Module included in the following assemblies:
+//
+// * virt/about-virt.adoc
+
+:_content-type: CONCEPT
+[id="virt-about-storage-volumes-for-vm-disks_{context}"]
+= About storage volumes for virtual machine disks
+
+If you use the storage API with known storage providers, volume and access modes are selected automatically. However, if you use a storage class that does not have a storage profile, you must select the volume and access mode.
+
+For best results, use `accessMode: ReadWriteMany` and `volumeMode: Block`. This is important for the following reasons:
+
+* The ReadWriteMany (RWX) access mode is required for live migration.
+
+* The `Block` volume mode performs significantly better in comparison to the `Filesystem` volume mode. This is because the `Filesystem` volume mode uses more storage layers, including a file system layer and a disk image file. These layers are not necessary for VM disk storage.
++
+For example, if you use {rh-storage-first}, Ceph RBD volumes are preferable to CephFS volumes.
+
+// the note below was in the original features-for-storage assembly
+[IMPORTANT]
+====
+You cannot live migrate virtual machines that use:
+
+* A storage volume with ReadWriteOnce (RWO) access mode
+
+* Passthrough features such as GPUs
+
+Do not set the `evictionStrategy` field to `LiveMigrate` for these virtual machines.
+====

modules/virt-features-for-storage-matrix.adoc

@@ -22,12 +22,16 @@ include::snippets/technology-preview.adoc[]
 
 include::modules/virt-supported-cluster-version.adoc[leveloffset=+2]
 
+include::modules/virt-about-storage-volumes-for-vm-disks.adoc[leveloffset=+1]
+
 include::modules/virt-sno-differences.adoc[leveloffset=+1]
 
 [role="_additional-resources"]
 [id="additional-resources_about-virt"]
 == Additional resources
 
+* xref:../storage/index.adoc#openshift-storage-common-terms_storage-overview[Glossary of common terms for {product-title} storage]
+
 * xref:../installing/installing_sno/install-sno-preparing-to-install-sno.adoc#install-sno-about-installing-on-a-single-node_install-sno-preparing[About {sno}]
 
 * link:https://cloud.redhat.com/blog/using-the-openshift-assisted-installer-service-to-deploy-an-openshift-cluster-on-metal-and-vsphere[Assisted installer]

virt/about-virt.adoc

@@ -30,6 +30,13 @@ include::modules/virt-hardware-os-requirements.adoc[leveloffset=+1]
 
 include::modules/virt-cluster-resource-requirements.adoc[leveloffset=+1]
 
+include::modules/virt-about-storage-volumes-for-vm-disks.adoc[leveloffset=+1]
+
+[role="_additional-resources"]
+.Additional resources
+
+* xref:../../storage/index.adoc#openshift-storage-common-terms_storage-overview[Glossary of common terms for {product-title} storage]
+
 [id="object-maximums_{context}"]
 == Object maximums
 
@@ -54,11 +61,6 @@ Live migration has the following requirements:
 * Sufficient RAM and network bandwidth.
 * If the virtual machine uses a host model CPU, the nodes must support the virtual machine's host model CPU.
 
-[id="snapshots-and-cloning_{context}"]
-== Snapshots and cloning
-
-See xref:../../virt/virtual_machines/virtual_disks/virt-features-for-storage.adoc#virt-features-for-storage[{VirtProductName} storage features] for snapshot and cloning requirements.
-
 // The HA section actually belongs to OpenShift, not Virt
 [id="cluster-high-availability-options_{context}"]
 == Cluster high-availability options

virt/install/preparing-cluster-for-virt.adoc

@@ -24,9 +24,11 @@ Plan and install {VirtProductName} on an {product-title} cluster:
 * xref:../virt/install/virt-installing-virtctl.adoc#virt-installing-virtctl[Install the `virtctl` command line interface (CLI) tool].
 
 [discrete]
-[id="additional-resources-planning-and-installing"]
+[id="additional-resources_planning-and-installing"]
 [role="_additional-resources"]
 === Planning and installation resources
+
+* xref:../virt/install/preparing-cluster-for-virt.adoc#virt-about-storage-volumes-for-vm-disks_preparing-cluster-for-virt[About storage volumes for virtual machine disks].
 * xref:../storage/container_storage_interface/persistent-storage-csi.adoc#persistent-storage-csi[Using a CSI-enabled storage provider].
 * xref:../virt/virtual_machines/virtual_disks/virt-configuring-local-storage-for-vms.adoc#virt-configuring-local-storage-for-vms[Configuring local storage for virtual machines].
 * xref:../networking/k8s_nmstate/k8s-nmstate-about-the-k8s-nmstate-operator.adoc#installing-the-kubernetes-nmstate-operator-cli[Installing the Kubernetes NMState Operator].
@@ -52,7 +54,7 @@ Manage the VMs:
 * xref:../virt/virtual_machines/virt-controlling-vm-states.adoc#virt-controlling-vm-states[Stop, start, pause, and restart a VM by using the web console].
 * xref:../virt/virt-using-the-cli-tools.adoc#virt-virtctl-commands_virt-using-the-cli-tools[Manage a VM, expose a port, or connect to the serial console by using the `virtctl` CLI tool].
 
-[id="next-steps"]
+[id="next-steps_{context}"]
 == Next steps
 
 * Connect the VMs to secondary networks: