I am actually seeing this issue at a couple of sites. Whenever a snapshot is deleted the network becomes unresponsive. Users in terminal server session lock up until the deletion is completed. Now if the snapshot is taken without snapshoting the memory the users do not see an issue.
The vranger backup software does not have a setting to snapshot without memory so I have no control over that process. Since some of my clients are 24 hour shops this is an issue. Is there any ESX configuration that will solve this issue so snapshot deletion does not cause connectivity issues?