3V0-23.25 Advanced VMware Cloud Foundation 9.0 Storage Questions and Answers

Both vSAN OSA and vSAN ESA require a trusted key provider before Data-at-Rest Encryption can be enabled. With a standard external KMS, the configuration process includes adding the KMS to vCenter and establishing trust with the KMS. vCenter then provisions encryption keys from the key provider. The vSAN encryption workflow uses a Key Encryption Key from the KMS to protect Data Encryption Keys used by ESX hosts. This requirement applies to vSAN encryption generally and is not limited to a specific vSAN architecture. OSA supports external KMS integration, so the option stating that OSA does not support external KMS integration is incorrect. Trusted Platform Modules are not mandatory prerequisites for either OSA or ESA. The vSphere key provider requirements state that TPM is not required for a standard key provider or for vSphere Native Key Provider, although Native Key Provider availability can optionally be restricted to hosts with TPMs. Therefore, the mandatory prerequisite is a trusted KMS identity for both OSA and ESA. Reference topics: vSAN Data-at-Rest Encryption, Standard Key Provider, KMS Trust, OSA and ESA Encryption Support, TPM Requirements.

The workload domain should use Fibre Channel as principal storage because the existing five hosts already have resilient HBAs and are connected to a dedicated, highly resilient storage area network. The third-party block storage is also stated to have sufficient scale, capacity, and IOPS for the new workload requirements only, so it should be reused where it directly fits: the VI workload domain. VMware Cloud Foundation supports Fibre Channel as both principal and supplemental storage for VI workload domains. The management domain should use VMware vSAN as principal storage because the four new servers are being purchased for the management domain, and the existing block storage is not sized for management workloads. vSAN is a native VCF principal storage model for management domains and provides automated deployment, policy-based management, lifecycle integration, and integrated operations. iSCSI is not the right answer because the scenario describes Fibre Channel SAN connectivity and HBAs, not an iSCSI design. vSAN for the workload domain would also fail the reuse requirement because it would ignore the existing block storage investment. Reference topics: Principal Storage, Fibre Channel Storage Model, vSAN Storage Model, Management Domain Storage.

vSAN ESA Storage Clusters are the optimal choice because the workload profile is capacity-heavy and benefits from disaggregated storage. The requirement for 2.5 PB of application data, archival workloads, gateways, and development/test applications indicates a need to scale storage capacity independently from compute resources. VMware Cloud Foundation describes a vSAN storage cluster as a disaggregated storage solution based on vSAN ESA. It provides storage resources but not compute resources, and its datastore can be mounted by vSAN compute clusters or vSAN HCI clusters. This model is designed for storage-dense environments where capacity and performance can be expanded without adding unnecessary compute. A standard vSAN ESA HCI cluster is excellent for high-performance workloads, but it scales compute and storage together. vSAN OSA all-flash and hybrid use the older disk-group architecture and are less suitable for this large-capacity, storage-centric design. Therefore, the principal storage recommendation should be vSAN ESA Storage Clusters to meet scalability, performance, and capacity growth requirements. Reference topics: vSAN Storage Cluster, Disaggregated Storage, vSAN ESA, Storage Models.

In a three-node vSAN ESA cluster, the maximum practical storage policy failure tolerance is one failure. RAID-1 mirroring with Failures to tolerate set to 1 is supported because vSAN can place mirrored data components across the available hosts while maintaining quorum. RAID-5 erasure coding with Failures to tolerate set to 1 is also supported in vSAN ESA three-host clusters. The documentation specifically states that RAID-5 in vSAN ESA supports three ESX host clusters. RAID-6 with FTT=2 is not supported because it requires at least six ESX hosts in the vSphere cluster. RAID-1 with FTT=2 would also require additional fault domains because vSAN requires 2n+1 fault domains for n failures tolerated. HA reserved failover capacity for CPU and memory does not change the number of vSAN fault domains available for storage object placement. It only affects compute admission control. Therefore, the two valid maximum protection levels for this three-node ESA cluster are RAID-1 mirroring with one failure and RAID-5 erasure coding with one failure. Reference topics: vSAN ESA Storage Policies, Failures to Tolerate, RAID-1 Mirroring, RAID-5 Erasure Coding, RAID-6 Requirements.

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 prerequisite is to enable vSAN on the non-vSAN cluster so it can operate as a vSAN compute cluster. A vSAN compute cluster is a vSphere cluster that does not contribute local vSAN capacity, but it has vSAN functionality enabled so it can mount a remote vSAN datastore provided by a vSAN Storage Cluster. The Datastore Management option under the vSAN section appears only when the consuming cluster is prepared for vSAN datastore sharing. Without vSAN enabled in compute-cluster mode, the vSphere cluster remains a conventional VMFS-backed cluster and cannot use the vSAN remote datastore management workflow. The cluster does not need to be in a different VCF Workload Domain, and there is no requirement that the storage cluster maintain exactly 80% free space before the option appears. A fourth host is also not required simply to mount remote vSAN capacity. The key requirement is enabling vSAN capability on the client cluster so it can communicate with and consume the remote ESA datastore. Reference topics: vSAN Compute Cluster, Remote vSAN Datastore, Datastore Management, vSAN Storage Cluster.

The two major contributors are RAID overhead and Operational Reserve. With the default policy set to FTT=1 using RAID-1 mirroring, vSAN stores two copies of protected data. The capacity planning guidance states that when Failures to tolerate is set to 1 failure with RAID-1 mirroring, virtual machines can use about 50 percent of raw capacity because each object consumes mirrored space. This is the largest capacity-impacting factor. The second contributor is Operational Reserve, which reserves capacity for vSAN internal operations such as policy changes, rebalancing, object movement, and other transient storage activities. Even when Host Rebuild Reserve is not activated, vSAN capacity monitoring still accounts for the operations threshold/reserve needed to keep the cluster functional during internal activity. Encryption overhead is typically not the primary reason for a 20% capacity difference. Host upgrade overhead is not a vSAN capacity category. VM swap can consume capacity, but it does not normally account for most unavailable raw capacity compared with RAID mirroring and operational reservation. Reference topics: vSAN Capacity Planning, RAID-1 FTT=1 Capacity Impact, Operations Reserve, Reserved Capacity.

vSAN object availability is based on two conditions: an intact replica must be available, and more than 50% of the object’s votes must be accessible. In this scenario, vSAN can locate a full replica and 55% of the votes for the noncompliant objects. Because 55% is greater than the quorum threshold, the objects remain available to the vSAN datastore. A noncompliant status means the VM objects do not currently satisfy the assigned storage policy, but it does not automatically mean the VM is inaccessible. The documentation states that if the operational state remains healthy although the object is noncompliant, the virtual machine can continue using the vSAN datastore. If the cluster contains enough resources and the failure is permanent, vSAN automatically recovers failed components and restores compliance. The VM is marked inaccessible only when a full replica cannot be located or when 50% or fewer votes are available. It becomes orphaned only if the VM namespace, such as the .vmx file, cannot be accessed. Reference topics: vSAN Object Health, Quorum Votes, Noncompliant Objects, Inaccessible and Orphaned VM States.

vSAN File Share SMB services are required because the storage must be consumed by Windows workstations and the application requires native NTFS permissions. SMB is the Windows-native file sharing protocol and integrates with Active Directory authentication. vSAN File Service supports SMB file shares, and Windows clients joined to the Active Directory domain configured with vSAN File Service can access those shares by using the SMB path. vSAN File Service also supports Microsoft Management Console for SMB shares, including Access Control List management, open file viewing, active sessions, and client connection management. These capabilities align directly with NTFS-style permission expectations for Windows-based graphic design workstations. vSAN File Service also supports two-node vSAN configurations, which matches the remote-site rack-space constraint of two hosts with a witness deployed remotely or in a shared location. NFSv3 does not provide native NTFS permissions for Windows clients. vSAN Storage Cluster and vSAN HCI Mesh address remote datastore capacity sharing, not SMB file access for Windows users. Reference topics: vSAN File Service, SMB File Shares, Active Directory Integration, Two-Node vSAN Support.

The user account used by the application.

The Active Directory used by the application.

The password used by the application.

NFSv4.1 with Kerberos requires identity integration through Active Directory and a valid Kerberos-capable user credential. In vSphere, Kerberos authentication for NFS 4.1 uses Active Directory credentials so ESX can authenticate securely when mounting Kerberos-protected NFS datastores. The required inputs are the Active Directory domain, the user account, and the password associated with that account. The storage guide also states that when several ESX hosts access the same NFS 4.1 datastore, all hosts must use the same Active Directory credentials to ensure consistent access. The Organizational Unit is not the required credential element for datastore mounting. The DNS name of a Kerberos server may be resolved through Active Directory and DNS infrastructure, but it is not one of the required configuration values selected here. A “Kerberos Key Management Server” is not part of the vSphere NFSv4.1 Kerberos datastore configuration model. Therefore, the required options are the application’s user account, its Active Directory, and the account password. Reference topics: NFSv4.1 Datastores, Kerberos Authentication, Active Directory Credentials, Kerberos Security for NFS.

Full Clone from Volume Snapshot

4kn Support

Online Volume Expansion

Offline Volume Expansion

Static Persistent Volume

VMware Kubernetes Service persistent volumes use vSphere storage integrations such as CNS and pvCSI to provide Kubernetes storage services backed by vSphere datastores and storage policies. The supported persistent volume capabilities include Static Persistent Volume, which allows pre-existing storage to be consumed by Kubernetes workloads; Offline Volume Expansion and Online Volume Expansion, which allow persistent volumes to be resized depending on workload and filesystem state; Full Clone from Volume Snapshot, which enables a new volume to be created from an existing snapshot; and 4kn Support, which supports modern 4K native storage devices where the underlying stack supports them. Storage vMotion with attached Persistent Volumes is not supported because moving an attached Kubernetes persistent volume while it is in active use can break attachment and consistency assumptions. Storage DRS is also not a supported persistent volume capability in this VKS context. Flash Read Cache is not part of the supported VKS persistent-volume capability set. Reference topics: VMware Kubernetes Service Storage, CNS, pvCSI, Persistent Volume Capabilities, Volume Expansion, Volume Snapshot Clone.

In vSAN ESA, the observed three disk stripes are expected behavior for objects using RAID-1, even when the storage policy shows “Number of disk stripes per object = 1.” The vSAN policy rule defines the minimum number of capacity devices across which each replica of an object is striped, and the default value is 1. However, VMware documentation explicitly notes that objects in a vSAN ESA cluster with RAID-0 or RAID-1 configuration have 3 disk stripes, even if the default storage policy defines only 1 disk stripe. Therefore, the three stripes are not caused by site mirroring itself, nor by the VM having three objects. Site mirroring controls placement across the preferred and secondary sites in a stretched cluster, while Failures to tolerate with RAID-1 controls local host/device protection. The behavior is also not evidence that a VM-level policy override exists. The datastore-level policy can still be applied correctly; ESA’s internal RAID-1 object layout uses three stripes as part of its optimized storage architecture. Reference topics: vSAN ESA Default Storage Policy Characteristics, Number of Disk Stripes per Object, RAID-1 Mirroring, vSAN Stretched Cluster Storage Policies.

Four hosts are required to meet the 12 TB usable-capacity requirement after applying the protection policy, data reduction, reserves, and overhead. Each host contributes 8 TB raw capacity from two 4 TB NVMe devices. Three hosts provide 24 TB raw capacity, but once host rebuild reservation, 10% operational reserve, RAID-5 protection overhead, and 25% filesystem/object overhead are considered, the remaining effective usable capacity falls below the required 12 TB target. Four hosts provide 32 TB raw capacity. With vSAN ESA and FTT=1/RAID-5, vSAN uses erasure coding to improve capacity efficiency compared with mirroring. The vSAN sizing guidance states that RAID-5 with FTT=1 provides approximately 75% usable capacity before other reserves and overhead. Host Rebuild Reserve must also be planned so the cluster has enough free capacity to rebuild components after a host failure. After applying the expected 1.5 data reduction ratio and the required reserves, four hosts provide enough usable capacity while three hosts do not. Reference topics: vSAN ESA Capacity Sizing, RAID-5 Erasure Coding, Host Rebuild Reserve, Operations Reserve, vSAN Object Overhead.

VMware vSAN is the correct principal storage for both the Management Domain and the Workload Domain because it is integrated, policy-based, scalable, and managed directly through VCF and vSphere. The Management Domain requirement explicitly calls for a highly scalable integrated storage solution that does not require additional storage management software or hardware, which aligns with vSAN. The Workload Domain also requires a highly scalable, policy-based storage solution for critical application workloads, which again maps directly to vSAN storage policies and vSAN datastore services. The second workload tier requires file-based storage that can scale independently of the cluster for workloads with large data requirements. NFS v3 is supported as supplemental storage and is appropriate for adding file-based capacity without changing the principal vSAN datastore. iSCSI is supplemental only and does not meet the Management Domain principal storage requirement. NFS v4.1 is not the correct principal storage selection for the Management Domain. Reference topics: VCF Storage Models, Principal Storage, Supplemental Storage, vSAN Storage Model, NFS Storage Model.

The two most relevant causes are insufficient vCenter permissions and incorrect DNS resolution. The VMware Live Recovery appliance must register with vCenter as a managed extension and service endpoint, so the account used during the Configure Appliance workflow must have the required vCenter privileges. A user that can authenticate but lacks registration or administration privileges can still cause the appliance registration to fail. DNS is equally critical because appliance registration depends on stable FQDN resolution, certificate validation, Lookup Service communication, and service endpoint registration. Forward and reverse DNS records must resolve correctly between the VMware Live Recovery appliance and vCenter Server. Deploying the appliance to a non-vSAN datastore is not the primary reason for vCenter registration failure. DHCP is not inherently invalid if the resulting address and DNS records are correct, though static addressing is usually preferred. A local Photon OS account on the VCSA is not the correct account type, but the direct technical issue is the lack of required vCenter permissions. Reference topics: vSAN Data Protection, VMware Live Recovery Appliance Registration, vCenter Permissions, DNS Forward and Reverse Resolution.

Site A = Data Site; Site B = Witness Site; Site C = Data Site; Site A ↔ Site C = Layer 3, RTT < 5 ms; Site A ↔ Site B = Layer 3, RTT < 200 ms; Site B ↔ Site C = Layer 3, RTT < 200 ms

Site A and Site C should be the data sites because Site A hosts production services and Site C has been commissioned to replace the capacity-constrained Site B. Site B should be used as the witness site because it has no space for additional physical hosts, and a vSAN witness appliance does not run workload VMs. A vSAN Stretched Cluster requires two availability zones for data nodes and a third site for the witness appliance. The data-site-to-data-site connection carries synchronous vSAN data traffic and must meet less than 5 ms RTT. The witness site carries metadata traffic only, so the data-site-to-witness links support higher latency, with less than 200 ms RTT for up to 10 hosts per site. Because the requirement specifically calls out minimizing disruption from STP, Layer 3 is the preferred network type between sites. VMware states that Layer 3 helps avoid STP redirecting traffic across undesirable links, such as constrained witness links. Reference topics: vSAN Stretched Cluster Network Design, Data Site and Witness Site Placement, Layer 3 Recommendation, RTT Requirements.

vSAN HCI Cluster = A cluster that provides both compute and storage to Virtual Machines;

vSAN Storage Cluster = A vSAN cluster that provides disaggregated storage for vSAN and vSphere clusters;

vSAN Compute Cluster = A vSphere cluster that does not have local vSAN storage, but instead, it mounts a remote vSAN datastore;

vSAN Stretched Cluster = A vSAN Cluster topology that extends a single logical vSAN cluster across two availability zones. A vSAN stretched cluster can tolerate a site failure.

These mappings describe the primary vSAN storage models used in VMware Cloud Foundation 9.0. A vSAN HCI Cluster is the traditional hyperconverged model where the same cluster provides compute resources and contributes local storage devices to the vSAN datastore for running virtual machines. A vSAN Storage Cluster is a disaggregated storage model based on vSAN ESA; it provides storage capacity and performance to other vSAN or vSphere clusters instead of primarily running workloads itself. A vSAN Compute Cluster is a vSphere cluster that does not contribute local vSAN capacity. Instead, it consumes a remote datastore exported by a vSAN Storage Cluster, enabling compute and storage to scale separately. A vSAN Stretched Cluster extends a single logical vSAN cluster across two availability zones or sites and uses a witness to maintain quorum, allowing workloads to tolerate a full site failure. These distinctions are essential for choosing between HCI, disaggregated storage, remote storage consumption, and availability-zone resilience. Reference topics: vSAN HCI Cluster, vSAN Storage Cluster, vSAN Compute Cluster, vSAN Stretched Cluster, VCF Storage Models.

NFS must be used as principal storage because the hosts have no local storage available. vSAN OSA and vSAN ESA both require local storage devices on the ESX hosts to create the vSAN datastore, so neither can be selected as principal storage in this design. NVMe over RDMA is supported as a high-performance NVMe over Fabrics transport in vSphere, but in the VCF storage model it is treated as supplemental storage rather than principal storage for workload domain creation. Therefore, NVMe over RDMA cannot be the initial principal datastore used to build the Workload Domain. NFS is the valid principal storage option from the provided choices, and after the Workload Domain is created, NVMe over RDMA can be added as supplemental storage for additional performance or capacity use cases. This build order satisfies the lack of local disks, uses a supported principal storage type, and allows the NVMe over RDMA design requirement to be met after the domain exists. Reference topics: Principal Storage, Supplemental Storage, NFS Storage Model, NVMe over RDMA, VCF Workload Domain Storage Design.

ESA evaluates available capacity and fault domains to satisfy policy compliance.

vSAN detects the failure and marks affected objects as non-compliant.

Resync completes and objects transition to Compliant status.

New components are instantiated on eligible capacity devices, and resync begins.

A failed NVMe device in a vSAN ESA cluster is handled as a storage pool device failure. vSAN first detects the failure and marks affected objects as non-compliant when their assigned storage policy requirements are no longer satisfied. ESA then evaluates available capacity and fault domains to determine whether replacement components can be placed in a way that restores compliance. If sufficient placement resources exist, vSAN creates new components on eligible capacity devices and begins resynchronization. After the resync completes, the affected objects transition back to Compliant status. The Repair Delay Timer is primarily associated with absent components, such as a host or device that may return, and is not the required step for a permanent NVMe failure. The administrator does not have to manually trigger Repair Objects Immediately for the normal automatic repair process. A full cluster rebalance is separate from repair and is not performed before rebuilding missing or degraded components. Reference topics: vSAN ESA Storage Pool Device Failure, Object Compliance, Automatic Reprotection, Resynchronization.

The cluster must not include hosts from different subnets or networks (L3).

The default management vSphere cluster must already be stretched.

The cluster must not include DPU-backed hosts.

The cluster must not share a vSAN Storage Policy with any other cluster.

To stretch a vSAN cluster in a VCF Workload Domain, the environment must satisfy specific VCF stretch prerequisites and avoid unsupported configurations. The default management vSphere cluster must already be stretched so the management plane remains available if an availability zone fails. The workload cluster must not include hosts from different subnets or Layer 3 networks because the stretch workflow expects supported site and network placement assumptions for the cluster being stretched. The cluster must also not include DPU-backed hosts, because clusters with DPU-backed hosts are excluded from this stretch operation. In addition, the cluster must not share a vSAN Storage Policy with any other cluster, because shared policies can create policy scope and compliance conflicts during stretch configuration. SSH does not need to be manually activated on all hosts as a prerequisite. The default management cluster being “not stretched” is the opposite of the required condition. Host self-signed certificates are not the listed blocking condition for this workflow. Reference topics: Stretch vSAN Cluster in VCF, Workload Domain Stretch Prerequisites, vSAN Storage Policy Constraints, Unsupported Stretch Configurations.