How to prevent DL for dirty data on cache of CloudArray

Hello,

I understand dirty data not replicated to cloud on cache of CloudArray is lost when a ESX server where CloudArray runs crashes.

Could you tell me how to prevent DL for the dirty data in that case?

When Cloudarray VM and cache volume are stored in external storage, like VNX or Isilon, if a ESX server crashes then can the CloudArray VM and cache volume be available on a new ESX server? Is that not entirely ensured?