Azure File snapshot size is set to 100Gi regardless of storage account type

[RomanBednar]

For Azure File sets snapshot size to 100Gi in csi.CreateSnapshotResponse without checking account type/tier:
https://github.com/openshift/azure-file-csi-driver/blob/2017ebe042618aab18392692e9a19413f586a19b/pkg/azurefile/controllerserver.go#L921

Azure Disk sets snapshot size correctly in the response based on the actual size:
https://github.com/kubernetes-sigs/azuredisk-csi-driver/blob/96bdedac083ca6df9470293d4498119047fe1bb8/pkg/azureutils/azure_snapshot_utils.go#L51

Example in documentation uses 100Gi volumes and premium storage class, in this case everything works fine: https://github.com/kubernetes-sigs/azurefile-csi-driver/tree/master/deploy/example/snapshot#azure-file-snapshot-feature

However this size is not correct when using standard account type and it should be possible to create snapshots of smaller size.

Driver log (snapshot creation):

I0805 13:50:54.050814       1 utils.go:101] GRPC call: /csi.v1.Controller/CreateSnapshot
I0805 13:50:54.050834       1 utils.go:102] GRPC request: {"name":"snapshot-1ebb9e21-d812-4849-9288-c89fd42f0b83","source_volume_id":"rbednar-mycluster-01-2wzgp-rg#f1de35e2654d34a73bbbb1a#pvc-bc5487c9-9f5e-4bb4-9c75-189556b376b3###default"}
I0805 13:50:54.558181       1 controllerserver.go:915] created share snapshot: 2024-08-05T13:50:54.0000000Z, time: 2024-08-05 13:50:54 +0000 UTC, quota: 0GiB
I0805 13:50:54.558239       1 utils.go:108] GRPC response: {"snapshot":{"creation_time":{"seconds":1722865854},"ready_to_use":true,"size_bytes":107374182400,"snapshot_id":"rbednar-mycluster-01-2wzgp-rg#f1de35e2654d34a73bbbb1a#pvc-bc5487c9-9f5e-4bb4-9c75-189556b376b3###default#2024-08-05T13:50:54.0000000Z","source_volume_id":"rbednar-mycluster-01-2wzgp-rg#f1de35e2654d34a73bbbb1a#pvc-bc5487c9-9f5e-4bb4-9c75-189556b376b3###default"}}

Origin PVC is 1Gi but snapshot is 100Gi:

$ oc get pvc
NAME    STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS    VOLUMEATTRIBUTESCLASS   AGE
pvc-1   Bound    pvc-bc5487c9-9f5e-4bb4-9c75-189556b376b3   1Gi        RWO            azurefile-csi   <unset>                 4m31s


$ oc get volumesnapshot
NAME             READYTOUSE   SOURCEPVC   SOURCESNAPSHOTCONTENT   RESTORESIZE   SNAPSHOTCLASS       SNAPSHOTCONTENT                                    CREATIONTIME   AGE
pvc-1-snapshot   true         pvc-1                               100Gi         csi-azurefile-vsc   snapcontent-1ebb9e21-d812-4849-9288-c89fd42f0b83   115s           116s

StorageClass is set to use non-premium storage account:

$ oc get sc/azurefile-csi -o yaml
allowVolumeExpansion: true
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  creationTimestamp: "2024-08-05T09:00:36Z"
  name: azurefile-csi
  resourceVersion: "7107"
  uid: 60bbaf5e-43ac-4b2c-b82a-841c01a3624f
mountOptions:
- mfsymlinks
- cache=strict
- nosharesock
- actimeo=30
parameters:
  skuName: Standard_LRS
provisioner: file.csi.azure.com
reclaimPolicy: Delete
volumeBindingMode: Immediate

NOTE:

Due to this behavior several upstream e2e tests are failing because they use volume sizes < 100Gi and assume snapshot size the be the same as origin PVC size. Then the origin PVC size is requested while restoring a (new) PVC from snapshot and test fails because the restore size is less than 100Gi.

Example test provisioning should provision correct filesystem size when restoring snapshot to larger size pvc:

0802 15:58:12.055378 849 dump.go:53] At 2024-08-02 15:48:10 +0000 UTC - event for pvc-xtrqj: {file.csi.azure.com_azure-file-csi-driver-controller-f4c5f8c6c-qqssg_81fa4cd0-db30-4147-90ec-5a3261ab93dc } ProvisioningFailed: failed to provision volume with StorageClass "e2e-provisioning-7878-e2e-scjjwcl": error getting handle for DataSource Type VolumeSnapshot by Name snapshot-plpg4: requested volume size 6442450944 is less than the size 107374182400 for the source snapshot snapshot-plpg4

[dobsonj]

@RomanBednar apparently the driver hard codes the snapshot size to 100GiB if the share quota is not set.

[RomanBednar]

Indeed, but I don't think this can be set by the user. But even if it can and I missed it, I don't understand the relation between quota (=max share size) and a size required to restore a snapshot, which is what the CSI response expects.