Nutanix NearSync replication provides low RPOs (1 to 15 minutes) by using " Lightweight Snapshots " (LWS). NearSync has higher performance and hardware requirements than standard Asynchronous replication because it must handle metadata operations and data transfers much more frequently.
For a cluster to support NearSync, it must have sufficient high-performance storage to handle the additional I
/O load associated with LWS. On hybrid nodes (those with both SSDs and HDDs), Nutanix has a specific hardware requirement: each node must have at least two SSDs. This is because the NearSync LWS metadata and incoming replicated data are initially written to the SSD tier to ensure low latency and high throughput. A single SSD per node is typically insufficient to handle both active VM production I/O and the high-frequency NearSync overhead without performance degradation. Therefore, adding a second SSD to each node (Option D) is the mandatory modification. While upgrading to NVMe (Option A) or adding more nodes (Option B) would also improve performance, adding a second SSD is the minimum " cost-effective " requirement specified by Nutanix engineering for NearSync support on hybrid clusters. Meeting these hardware prerequisites is essential to ensure that the cluster can maintain the 15-minute RPO without transitioning back to an hourly schedule due to resource constraints.

Nutanix NearSync replication provides a middle ground between traditional asynchronous replication and synchronous mirroring, offering RPOs as low as 1 minute using Lightweight Snapshots (LWS). However, the LWS mechanism and the high-frequency metadata operations required to maintain a 1-to-15 minute RPO have specific hardware and cluster-level requirements.
One of the strict prerequisites for enabling NearSync is the cluster size. Nutanix requires a minimum of a three-node cluster for NearSync replication. This is because the system must have enough resources to distribute the LWS metadata and handle the increased I/O overhead without compromising the cluster ' s availability or performance. In a two-node cluster (which is common for small ROBO deployments), the system does not meet the minimum redundancy and resource thresholds required for the NearSync engine to operate reliably. While two-node clusters support standard Asynchronous replication (with a 60-minute RPO or higher), they are restricted from using the NearSync lightweight snapshot engine. An administrator attempting to set a 5-minute RPO on a two-node cluster will find the option either grayed out or the task will fail validation. To achieve a 5-minute RPO, the organization would need to expand the remote office cluster to at least three nodes or settle for a higher RPO supported by standard asynchronous replication on the existing hardware.

Migrating from legacy Protection Domains to modern Prism Central Protection Policies involves transitioning the management of virtual machine snapshots. During this process, the historical snapshots created by the Protection Domain are often intended to be " claimed " or utilized by the new PC-based system as valid recovery points.
Snapshots are point-in-time references to data on the storage tier. If a snapshot is deleted from the cluster before the migration to Protection Policies is finalized, the underlying data blocks associated with that specific point in time may be reclaimed by the system ' s garbage collection process. Consequently, the recovery points that were associated with that deleted snapshot will no longer be available for use within the new deployment. The system cannot " automatically recreate " (Option A) a deleted snapshot because the exact historical state of the data is lost once the snapshot is purged. The migration itself typically continues for the remaining valid data, but the loss of historical recovery points could impact the business ' s ability to restore to specific past dates. This highlights the importance of data retention awareness during management-plane migrations.

Troubleshooting replication failures requires analyzing the relationship between snapshot creation and data transfer. In this scenario, the failure occurs during the snapshot creation phase rather than during the transfer of data across the wire. While network spikes and I/O timeouts are noted (Option D), these are often symptoms rather than the root cause when the specific failure point is the snapshot itself .
If multiple replication jobs or protection policies are scheduled to run at the exact same time, the cluster may experience " snapshot contention " or metadata locks. When schedules overlap significantly, the overhead on the Controller VMs (CVMs) can lead to the observed I/O timeout errors in the guest OS as the system struggles to quiesce applications and freeze the filesystem multiple times in quick succession. This is particularly common in environments with high data change rates where the previous replication cycle has not finished before the next one begins. Since storage is sufficient (Option B) and the clusters are compatible (Option E), the most logical cause is schedule misconfiguration. To resolve this, the administrator should stagger the start times of protection policies or combine multiple VMs into a single, unified policy to ensure that the Nutanix snapshot engine can process the requests sequentially without causing the resource exhaustion that leads to job failure.