Hello,
While the vdisk is in quarantine you cannot access it from the hosts. The only way to access the data on the vdisk is to de-quarantine and then take an immediate backup. Your problem is the vdisk is not stable with the number of failed and leftover drives. So your time to access the vdisk might be limited before it goes offline again. Which is why I was recommending getting critical data first.
Opening a support case is also highly recommended. Reviewing the logs would provide some insights to possibly getting the vdisk into a critical state so you can backup more data. Whihle this might not be full recovery it would give you more time to get a better backup of your data.
Cheers,
Shawn
I work for Hewlett Packard Enterprise. The comments in this post are my own and do not represent an official reply from HPE. No warranty or guarantees of any kind are expressed in my reply