Option to choose refquota zfs field to apply quotas

[tahajahangir]

Describe the problem/challenge you have
Currently, PVC sizes are applied using zfs quota field. This way, taking snapshot of a volume, decreases the available space of the PVC. I think this is not the desired behavior for many users.

Describe the solution you'd like
A simple solution is using refquota instead of quota.
A better solution is adding an option (operator-wide, per StorageClass or per PVC) to apply limits with refquota.
Another solution is provide a way (e.g. with annotations) to apply quota and refquota limits independently. For example, we can use the capacity property of PVC for refquota, and provide an annotation for limiting the zfs quota.

Environment:*

• Not important

[rdegez]

We have the exact same issue and I wonder how many people are actualy using snapshots in production without this!

[Abhinandan-Purkait]

@sabzsystem I see a PR was raised to address this? Why was this closed?

We can take this up as a roadmap item. Thanks

[niladrih]

Continuing the discussion here @cinapm.

I have one issue with #542: I think the CSI driver shouldn't be pinned to the quota/refquota choice it made at deploy time. It should be configurable via a storageClass parameter. Admins could choose if the provisioner uses quota/refquota at provision based on the StorageClass configuration.

I'm not a ZFS pro, but does the quota affect volume expansion?

@tiagolobocastro @avishnu @dsavitskiy you thoughts?

[Abhinandan-Purkait]

The functionality has been added as part of PR #542 . Will try to add a test for the change before we close this issue.