Revision Counter is enabled by default.
It is an UI typo.
https://github.com/longhorn/longhorn-ui/blob/master/src/routes/volume/detail/VolumeInfo.js#L326

Could you please check the revision counter setting inside the Setting CR?

kubectl get settings.longhorn.io disable-revision-counter -n longhorn-system

The value should be false for disable-revision-counter.
Therefore, the revision counter is enabled by default https://longhorn.io/docs/1.2.2/references/settings/#disable-revision-counter

Yup, seems false:

❯ kubectl get settings.longhorn.io disable-revision-counter -n longhorn-system
NAME                       VALUE   AGE
disable-revision-counter   false   327d

Cool, so it's just a confusing UI that needs improving. Probably just upgrading the label or inverting the if.

Pre Ready-For-Testing Checklist

• Where is the reproduce steps/test steps documented?
  The reproduce steps/test steps are at:

• Is there a workaround for the issue? If so, where is it documented?
  The workaround is at:

• Does the PR include the explanation for the fix or the feature?

• Does the PR include deployment change (YAML/Chart)? If so, where are the PRs for both YAML file and Chart?
  The PR for the YAML change is at:
  The PR for the chart change is at:

• Have the backend code been merged (Manager, Engine, Instance Manager, BackupStore etc) (including backport-needed/*)?
  The PR is at

• Which areas/issues this PR might have potential impacts on?
  Area
  Issues

• If labeled: require/LEP Has the Longhorn Enhancement Proposal PR submitted?
  The LEP PR is at

• If labeled: area/ui Has the UI issue filed or ready to be merged (including backport-needed/*)?
  The UI issue/PR is at

• If labeled: require/doc Has the necessary document PR submitted or merged (including backport-needed/*)?
  The documentation issue/PR is at

• If labeled: require/automation-e2e Has the end-to-end test plan been merged? Have QAs agreed on the automation test case? If only test case skeleton w/o implementation, have you created an implementation issue (including backport-needed/*)
  The automation skeleton PR is at
  The automation test case PR is at
  The issue of automation test case implementation is at (please create by the template)

• If labeled: require/automation-engine Has the engine integration test been merged (including backport-needed/*)?
  The engine automation PR is at

• If labeled: require/manual-test-plan Has the manual test plan been documented?
  The updated manual test plan is at

• If the fix introduces the code for backward compatibility Has a separate issue been filed with the label release/obsolete-compatibility?
  The compatibility issue is filed at

Validated on master-head, v1.2.x-head and v1.1.3-head - 12/08/2021

Validation - Pass

The label is changed to Revision Counter Disabled