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Recommended changes for DOCPLAN#185 #111769

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Recommended changes for DOCPLAN#185
rheslop May 15, 2026
dcf4fe6
Revert modules/hcp-virt-map-storage.adoc
rheslop May 20, 2026
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5 changes: 5 additions & 0 deletions modules/virt-about-storage-volumes-for-vm-disks.adoc
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Expand Up @@ -19,6 +19,11 @@ For best results, use the `ReadWriteMany` (RWX) access mode and the `Block` volu
* `ReadWriteMany` (RWX) access mode is required for live migration.
* The `Block` volume mode performs significantly better than 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.

[IMPORTANT]
====
You must use `Block` volume mode with `ReadWriteMany` (RWX) access mode for virtual machine disks. The `Filesystem` volume mode is not supported with RWX access mode for VM storage.
====

ifndef::openshift-rosa,openshift-dedicated,openshift-rosa-hcp[]
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For example, if you use {rh-storage-first}, Ceph RBD volumes are preferable to CephFS volumes.
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5 changes: 3 additions & 2 deletions modules/virt-configuring-vm-disk-sharing.adoc
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Expand Up @@ -27,9 +27,10 @@ If the VMs that are sharing disks are running on the same node, `ReadWriteOnce`
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[NOTE]
====
Not all filesystem and format combinations support RWX mode. For example, XFS format does not support RWX mode. When multiple VMs write to an XFS-formatted volume, data corruption occurs and only the writing VM can access the data.
====
The persistent volume claim (PVC) must use `Block` volume mode with `ReadWriteMany` (RWX) access mode. The `Filesystem` volume mode is not supported with RWX for virtual machine disks.

Not all guest filesystems support concurrent access. For example, XFS does not support `RWX` mode and can experience data corruption when shared between VMs.
====

* The storage provider must support the required Container Storage Interface (CSI) driver.

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5 changes: 5 additions & 0 deletions modules/virt-customizing-storage-profile.adoc
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Expand Up @@ -56,3 +56,8 @@ status:
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* `spec.claimPropertySets.accessModes` defines how the volume can be mounted. For example, `ReadWriteOnce`
* `spec.claimPropertySets.accessModes.volumeMode` defines whether the volume uses a file system or raw block storage. For example, `volumeMode`.
+
[IMPORTANT]
====
The `Filesystem` volume mode is not supported with `RWX` access mode for VM storage. Use `RWX` access mode only when `volumeMode` is `Block`.
====
2 changes: 1 addition & 1 deletion modules/virt-enabling-persistent-efi.adoc
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Expand Up @@ -21,7 +21,7 @@ ifdef::openshift-dedicated[]
* You must have a storage class that supports filesystem (`FS`) volume mode and the access mode required for persistent EFI state.
endif::openshift-dedicated[]
ifndef::openshift-dedicated[]
* You must have a storage class that supports RWX access mode and FS volume mode.
* You must have a storage class that supports RWX access mode and Block volume mode.
endif::openshift-dedicated[]
* You have installed the {oc-first}.

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2 changes: 1 addition & 1 deletion modules/virt-storage-wizard-fields-web.adoc
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Expand Up @@ -73,7 +73,7 @@ ifndef::openshift-dedicated[]
|ReadWriteOnce (RWO)
|Volume can be mounted as read/write by a single node.
|ReadWriteMany (RWX)
|Volume can be mounted as read/write by many nodes at one time.
|Volume can be mounted as read/write by many nodes at one time. You can only use RWX access mode with the `Block` volume mode.
[NOTE]
====
This mode is required for live migration.
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