Kentico 13 Media Files Usage Index

Hi,

I'm trying to understand the "Media Files Usage" local index.

We run in azure, Client and Admin run on separate Web Apps, and the Client site runs from package, so doesn't have write permission to App_Data.

So last year we were getting multiple errors in the local index task, so I patch to the latest version to allow me to disable the media file usage index. Which prevented the errors and didn't cause us any issues.

Now we would like to re-enable as we would like the usage stats. But if I rebuild the index it runs for the CMS and for the client site. The CMS completes and seems to work showing the usage, but the Client errors with "Error while processing index MediaFilesUsage: An error occurred while obtaining the index writer.".

I don't understand why the task needs to run on the Client site, but I can't see a way to disable.

I cleared the error and ran the "Execute local search tasks" task and it didn't appear to generate an error. Do this just execute the CMS task?

Thanks

Mat