// Module included in the following assemblies:
//
// * storage/container_storage_interface/persistent-storage-csi-sc-manage.adoc
//
:_mod-docs-content-type: CONCEPT
[id="persistent-storage-csi-sc-multiple-none_{context}"]
= Absent or multiple default storage classes

[role="_abstract"]
Absent or multiple default storage classes cause persistent volume claim issues. Multiple default storage classes might result in unpredictable selection and alerts, while absent default storage classes leave claims pending. Resolve by ensuring exactly one storage class is designated as the default.

== Multiple default storage classes
Multiple default storage classes can occur if you mark a non-default storage class as default and do not unset the existing default storage class, or you create a default storage class when a default storage class is already present. With multiple default storage classes present, any persistent volume claim (PVC) requesting the default storage class (`pvc.spec.storageClassName`=nil) gets the most recently created default storage class, regardless of the default status of that storage class, and the administrator receives an alert in the alerts dashboard that there are multiple default storage classes, `MultipleDefaultStorageClasses`.

== Absent default storage class
There are two possible scenarios where PVCs can attempt to use a non-existent default storage class:

* An administrator removes the default storage class or marks it as non-default, and then a user creates a PVC requesting the default storage class.

* During installation, the installer creates a PVC requesting the default storage class, which has not yet been created.

In the preceding scenarios, PVCs remain in the pending state indefinitely. To resolve this situation, create a default storage class or declare one of the existing storage classes as the default. As soon as the default storage class is created or declared, the PVCs get the new default storage class. If possible, the PVCs eventually bind to statically or dynamically provisioned PVs as usual, and move out of the pending state.