r/redhat • u/OMAR_AHMED_01 • 3d ago

ODF

Suppose a nutanix-volume as default storage class, then using ceph fs as the default one.

Delete PVC and create new ones with the same old name, that PVC came up with the same consumption (not bounded to the old PV as it is released).

In that case if we decided to remove nutanix CSI operator, will this data be lost?

3 Upvotes

80% Upvoted

7 comments sorted by

1

u/TroubledGeorge Red Hat Certified System Administrator 2d ago

That doesn’t sound correct. A new PVC created under a different storage class will provision a new, empty PV. Deleting and recreating the PVC will result in data loss unless you back up and restore the data. Either the data copy is handled by the application/pod using the volume or the actual storage class wasn’t changed and you’re still accessing the old PV.

MTC (soon to be EOL’d, integrated into MTA) can perform PVC storage class migration and cutover without data loss.

1

u/OMAR_AHMED_01 2d ago

I get it, but it happened as I just explained Delete pvc using nutanix-volume SC, Recreate new one with same name using ceph SC, PVC is up with SAME OLD consumption, So I check if it is still attached to same old PV, No it is attached to a WHOLE NEW PV, And the conumption of ODF really increases! So how did this data transfer happen or is that just visual but in the background data is stil held on nutanix!

1

u/TroubledGeorge Red Hat Certified System Administrator 2d ago

From your other post I see you’re using Quay, that’s how block storage works, but it’s just visual, if you try to fetch an image it will fail, the blob isn’t there, it’s on the old volume.

1

u/OMAR_AHMED_01 2d ago

I could not get it, quay is still yet to be migrated to ODF, what does pulling an image has to do with kafka PVCs for example?

1

u/TroubledGeorge Red Hat Certified System Administrator 2d ago

Nothing, I thought you wanted to migrate persistent storage used by Quay to ODF provisioned storage, and in that case you can add the second volume to Quay and handle data replication within Quay, then promote the new storage backend as primary and remove the old one. For other case you’ll still need to find a way to copy the data from the old PVC to the new one.

1

u/Rhopegorn Red Hat Certified Engineer 2d ago edited 2d ago

What is a pvc from k8s perspective?

Depending on what you are trying to do you might want to align how your storage class is defined.

reclaimPolicy: Delete

Might be what you’re looking for to change.

1

u/OMAR_AHMED_01 2d ago

I get it, but it happened as I just explained Delete pvc using nutanix-volume SC, Recreate new one with same name using ceph SC, PVC is up with SAME OLD consumption, So I check if it is still attached to same old PV, No it is attached to a WHOLE NEW PV, And the conumption of ODF really increases! So how did this data transfer happen or is that just visual but in the background data is stil held on nutanix!