Windows Server Failover Cluster shared disks require coordinated access to shared block storage.
vSAN supports Windows Server Failover Clusters by providing SCSI-3 Persistent Reservation support at the virtual disk level, which allows cluster nodes to arbitrate access to a shared disk resource. One supported approach is to use the vSAN iSCSI Target Service, which presents vSAN-backed LUNs to initiators and can be used for clustered workloads that require shared block access. Another supported approach is to configure a shared virtual disk using a VMware Paravirtual SCSI controller with physical bus sharing. Physical bus sharing allows multiple VMs to access the same shared virtual disk in a WSFC configuration where supported. Raw Device Mapping is not the vSAN ESA-native solution for this requirement. NFS v4.1 is a file datastore protocol, not a WSFC shared block disk mechanism.
"LSI SCSI controller per disk" does not satisfy the required shared-disk bus sharing configuration.
Reference topics: vSAN Support for Windows Server Failover Clusters, SCSI-3 Persistent Reservations, vSAN iSCSI Target Service, Shared VMDK Configuration.

The direct action is to convert the latency-sensitive OLTP workload policy from RAID-5/6 erasure coding to RAID-1 mirroring while keeping FTT=1. RAID-5/6 provides space efficiency, but it introduces parity operations and additional backend I/O, which can increase write latency during peak transactional activity and resynchronization. VMware states that RAID-1 mirroring requires fewer I/O operations to the storage devices and can provide better performance; cluster resynchronization also completes faster with RAID-1. This directly addresses the observed symptom: resync I/O and backend congestion increasing latency despite adequate network bandwidth. Increasing Object Space Reservation to 100% changes capacity preallocation but does not remove parity overhead or reduce write amplification from erasure coding. Increasing FTT to 2 with RAID-5/6 would increase protection overhead and backend work, making latency worse. Disabling checksums is not valid for ESA because object checksum is always enabled and cannot be deactivated. For ESA, compression can be controlled by policy, but the most direct protection-compliant performance action is RAID-1 FTT=1 for OLTP objects. Reference topics: vSAN Storage Policies, RAID-1 Mirroring, RAID-5/6 Erasure Coding, vSAN ESA Checksum, Resync and Congestion Metrics.

With "Ensure Accessibility," vSAN migrates only the minimum amount of data required to keep objects accessible while the host enters maintenance mode. This mode is faster than Full Data Migration, but it does not fully reprotect all objects. The documentation states that objects might no longer be fully compliant with their storage policy during this evacuation mode, meaning they might not have access to all replicas. Because the default policy is RAID-1 with FTT=1, each object can tolerate only one failure. While the first host is in maintenance mode, some VM objects are already running in a reduced-availability state. If a second host loses network connectivity during this window, affected objects can lose quorum or access to required components.
vSAN does not immediately rebalance or fully rebuild objects simply because Ensure Accessibility was selected, and permanent data loss is not the expected result from a temporary network loss. The likely impact is that some VMs become inaccessible until either the maintenance host returns or the isolated host reconnects. Reference topics: vSAN Maintenance Mode, Ensure Accessibility, Default Storage Policy, RAID-
1 FTT=1, Network Partition Handling.

After vSAN File Services has been deployed, the editable settings are primarily related to the File Service domain network configuration. The vSAN File Service workflow allows modification of primary IP addresses, static IP addresses, and DNS names. These values define how the file service endpoints are presented to clients and how file server instances are resolved on the network. The File Service domain can be adjusted by editing the network configuration and adding or removing IP addresses as needed. The Active Directory domain is not treated as a simple post-deployment editable field because changing domain membership can disrupt authentication, permissions, and file-share access. The Active Directory username and Organizational Unit are part of the directory integration and domain-join configuration, but they are not the three standard settings identified for modification after the initial File Services configuration. Therefore, the three modifiable settings are Static IP addresses, Primary IP addresses, and DNS names. Reference topics: vSAN File Service, Edit File Service Domain, File Service Network Configuration, Active Directory Integration.

The Live! vSphere Heavy Hitter VM dashboard is the correct place to identify which virtual machines are driving storage IOPS and disk throughput problems. In VCF Operations, heavy hitter dashboards are designed to isolate the consumers creating the highest demand on shared infrastructure resources.
For storage troubleshooting, this dashboard identifies VMs producing significant I/O load, including IOPS and throughput. This is especially useful when a Fibre Channel datastore is reporting performance alerts because the datastore itself may show contention, but the root cause is often one or more high-demand VMs consuming disproportionate backend storage resources. The vSAN Health dashboard is not correct because the affected datastore is Fibre Channel, not vSAN. The vSphere Storage Inventory dashboard is useful for topology and inventory visibility, but it is not the best view for identifying the VM-level consumers causing IOPS and throughput pressure. The Storage Operations page is broader and less targeted than the Live heavy hitter view. Reference topics: VCF Operations Performance Dashboards, Storage Heavy Hitters, VM IOPS and Throughput Troubleshooting.