4.4.4. Important Notes and Known Issues

AccessMode

The Kubernetes AccessMode field in a PVC can receive the following values:
(reference K8s Docs – Volume AccessMode)

• ReadWriteOnce – the volume can be mounted as read-write by a single node
• ReadOnlyMany – the volume can be mounted read-only by many nodes
• ReadWriteMany – the volume can be mounted as read-write by many nodes
  

*Kubernetes AccessModes as defined today, only describe node attach (not pod mount) semantics. For example when using AccessMode: ReadWriteOnce The NVMesh CSI Driver will allow the attach to happen only on one node BUT does not guarantee that 2 pods running on the same node will not access the volume at the same time.

FileSystem Volumes

When creating a FileSystem Volume the CSI Driver currently supports only non-shared File Systems (ext4 and xfs)
This means that the user should make sure that no more than one POD is writing to the Volume at the same time, and multiple readers might not have the most updated data.
About using the PVC AccessMode field please see below.

To deploy any other file system, please create a BlockVolume and deploy the file system after the volume was created.

!When FileSystem Volume is used Make sure you have configured the consuming PODS to have only one writer at a time. having multiple writers might cause the attach process to hang making the volume unusable.