Self-Service Restore (SSR) relies on the Nutanix Guest Tools (NGT) agent to mount a historical snapshot disk to the guest OS via the hypervisor ' s virtual controller. For this to work seamlessly, the guest OS and the NGT agent must support the virtual bus types used by the virtual machine.
Nutanix SSR natively supports the two most common virtual disk controller types: SCSI (VirtIO) and IDE.
These are the standard formats for most virtual disks in Nutanix AHV and ESXi environments. When a user requests a file-level restore, the system takes the vDisk from the recovery point and attaches it as a new SCSI or IDE device to the running VM, which the guest OS then scans and mounts. Conversely, specialized storage entities like Volume Groups (VGs) (Option D) and certain high-performance direct-attached PCI-based storage (Option C) are not supported by the standard SSR workflow. Volume Groups, which are often used for shared storage between VMs (like SQL Clusters), require a different recovery method because they are not part of the standard VM-centric snapshot metadata that the SSR agent can browse. Therefore, SSR is primarily designed for the standard virtual disks that form the OS and application drives of typical virtualized workloads.

Nutanix supports software-based data-at-rest encryption for AHV workloads. This encryption is typically managed through " Storage Policies " in Prism Central, which are applied to virtual machines based on their " Categories " . For example, a policy might state that any VM in the Compliance:Encrypted category must have its data encrypted on the disk.
When a failover occurs, the VM moves to the recovery cluster. While the data that was replicated is already encrypted, the " Active " Storage Policy at the recovery site must be verified. If the recovery cluster does not have the same Storage Policy configuration or if the VM-to-Policy association was lost during the transition, the AOS storage engine at the recovery site will treat the VM as a standard, non-encrypted workload. This results in " newly written data " (writes occurring after the failover) being stored in plain text. To fix this, the administrator must " reassign " or refresh the Storage Policies and Categories at the recovery site. This ensures that the encryption rules are actively enforced on the new cluster, maintaining the organization ' s security posture post-disaster. This cleanup step is vital for compliance-heavy environments where encryption- at-rest is a mandatory requirement.

The Recovery Point Objective (RPO) is a measure of how much data an organization can afford to lose during an outage. An RPO of zero means that absolutely no data loss is tolerated; every write performed at the primary site must be safely committed to the recovery site before the application receives a confirmation. In the Nutanix portfolio, Synchronous Replication (Option A) is the only technology that guarantees this level of data protection. It mirrors every write in real-time between two clusters, ensuring they are always in perfect synchronization. In contrast, Nearsync Replication (Option B) allows for very low RPOs (as low as 20 seconds to 1 minute), but it is still fundamentally an asynchronous process using lightweight snapshots, meaning some " data-in-flight " could be lost. Async Replication (Option C) typically involves RPOs of one hour or more and is used for less critical workloads. Cloud Connect (Option D) is a legacy feature for off-site backup and does not support zero-RPO requirements. Synchronous Replication is the " gold standard " for Tier-1, mission-critical applications where data integrity and zero loss are the primary business requirements, provided the network latency between sites is 5ms or less.

Synchronous replication is a high-performance disaster recovery solution designed to provide a Zero Recovery Point Objective (RPO) by mirroring every write operation in real-time between two clusters.
Because the system must wait for the remote site to acknowledge every write before confirming the operation to the application, the underlying storage media must be capable of extremely low-latency I/O.
On hybrid clusters that utilize both Solid State Drives (SSDs) and Hard Disk Drives (HDDs), Nutanix mandates a minimum of one SSD per node to support synchronous replication. The SSD tier is used to store metadata and provide the high-speed " Oplog " where incoming writes are initially landed before being drained to the HDD tier. If a cluster were to attempt synchronous replication using only HDDs (Option D), the mechanical latency of the spinning disks combined with the network Round Trip Time (RTT) would cause severe application performance degradation, failing the business requirement. Even though the cluster has large capacity requirements (100 TB), the presence of an SSD tier is a technical prerequisite for the software to even enable the synchronous consistency feature. Therefore, ensuring at least one SSD exists in every node of the hybrid cluster is the critical storage validation step required before implementation.

Nutanix Metro Availability is a continuous availability solution that provides a zero Recovery Point Objective (RPO) and near-zero Recovery Time Objective (RTO) across two sites. For this configuration, there are two distinct latency requirements that administrators must manage. First, the Round Trip Time (RTT) latency between the two storage clusters participating in the synchronous replication must be less than 5ms to ensure application performance is not significantly degraded by the write-synchronization process. Second, the Witness VM, which acts as an external arbitrator to prevent " split-brain " scenarios during a site failure, has a more flexible latency requirement. The maximum RTT between the Witness VM and the managed Protection Domains (PDs) must be less than 200ms. This higher threshold allows the Witness to be placed in a separate geographical region or a third-party cloud availability zone (AZ), ensuring it remains independent of the failure domain affecting the primary and secondary sites. If the latency to the Witness exceeds 200ms, the cluster may be unable to quickly acquire the lock necessary to automate failover, potentially causing the Metro Availability configuration to fail during an actual disaster event.