You're going to have to explain your network topology a little bit better because there are many gaps here.
How many hosts do you have?
What backup products are you using? You mentioned veritas and veeam, but what does that mean?
3 host and used. All virtual machines are hosted on the server. All hosts are connected to the SAS repository. This storage contains disks of the virtual machine that hosts Veritas Backup. Colleagues suggested that you need to use HotAdd, so as not to load the network. But when backing up, get out the error VixDiskLib_Open ()