Well – I have been asked asked a question about the Backup failure of Quorum disk

if we have failure and if we are using the Quorum disk as only and only Quorum disk then you can exclude the disk from the backups
Reason : the backup generally fails in the Log* files due the open and write operations of logs by the cluster service  and hence server can alert the backup failure & as we all aware we have open file backup as well but I suggest not to go for backup only for Quorom DIsk

thanks
Aslam