Nutanix Volume Groups (VGs) provide block-level storage to virtual machines, often used for high-performance databases or shared storage clusters. Unlike standard vDisks, which are managed directly as part of the VM ' s hardware definition, VGs are presented as iSCSI targets. In a Disaster Recovery scenario, when a VM is recovered at a new site, it must be able to " find " and re-attach these Volume Groups to resume operation.

For this attachment to succeed, especially across different clusters or into a Nutanix Cloud AZ, both the source and recovery clusters must have a " Data Services IP Address " configured. The Data Services IP acts as the cluster-wide iSCSI target portal. When a VM fails over, the Nutanix orchestration engine uses this IP to coordinate the iSCSI login and mapping of the Volume Group to the guest OS. If this IP is missing on either cluster, the internal iSCSI redirection and handoff mechanisms will fail, even if the general management networking and Protection Policies are perfectly healthy. This is a common " Day 1 " configuration error because management connectivity (Prism) works without a Data Services IP, but block-level services like VGs and certain NGT features strictly require it. Verifying and configuring the Data Services IP at both availability zones is the primary fix for Volume Group attachment failures during DR failover.