How to Setup Dataset Scale-Out

Hi tk6, it looks like the XMLA request succeeded. At least that's what an empty XMLA response like the one you posted above implies. It might be worth checking the syncStatus API, but if your refresh is still failing, the replicas might still be on the same version. Note that refresh isolation does not automatically lower the memory requirements of your refresh. You would have to change the refresh methodology. My recommendation, start with a small evaluation dataset first. If you place it in the same workspace and configure it to use the large storage format, scale-out should be enabled by default because you have it enabled on the workspace. Then refresh this small dataset. Check the syncStatus. Replicas should be out of sync. Then manually sync the replicas. Then try things like Process Clear. Then read replica should be unaffected because you aren't syncing yet. Then do a Process Full and then a sync. Everything should be back in good shape. Once you are confident, try this approach on the larger dataset to see if it helps you lower the memory footprint of your dataset refresh on the read/write replica. 
Hope this helps,
Cheers,

Kay