Windows Server 2025 Datacenter with Hyper-V and Storage Spaces Direct

Two servers for Storage Spaces Direct.

16 servers per S2D cluster (over 400 drives, 4 PB). Hyper-V failover clusters on SAN reach 64 nodes and 8,000 running VMs.

Not for S2D (minimum two servers). A standalone Hyper-V host with local Storage Spaces works but has no HA.

Supported, switched or switchless, with nested resiliency. Witness options: file share, cloud (Azure Storage), disk or USB witness.

S2D stretch clusters with Storage Replica between sites (synchronous under 5 ms RTT). S2D campus clusters (Dec 2025 update) span two racks at 1 ms or less, up to 5+5 nodes.

Converged deployments put Scale-Out File Server on S2D so compute clusters scale separately; SAN-backed and mixed architectures also supported.

Full support for Fibre Channel, iSCSI and SMB 3 storage, alone or alongside S2D in the same cluster.

All-NVMe and persistent-memory S2D supported; Windows Server 2025 adds an optimised NVMe stack with more IOPS and less CPU.

ReFS native deduplication and compression (new in 2025), plus classic Data Deduplication. Post-process.

Dual parity from 4 servers (50-80% efficiency) and mirror-accelerated parity; single parity from 3 servers (discouraged).

Two-way and three-way mirror, nested resiliency for 2 nodes, dual parity, chassis/rack fault domains and Rack Level Nested Mirror for campus clusters.

Hyper-V checkpoints (up to 50 per VM), ReFS block cloning, and thin-provisioned S2D volumes in 2025.

BitLocker (including on Cluster Shared Volumes) with TPM; shielded VMs with Host Guardian Service in Datacenter. Configured by the admin, not on by default.

Storage QoS: minimum and maximum IOPS and bandwidth policies per VM or virtual disk.

Native SMB 3 (including SMB over QUIC and Scale-Out File Server) and NFS server roles.

No native S3-compatible object storage.

iSCSI Target Server role and Scale-Out File Server (SMB 3) can present S2D capacity to other hosts.

Hyper-V Replica (30 s, 5 min or 15 min) and Storage Replica asynchronous volume replication, with compression in 2025.

Storage Replica synchronous block replication (zero RPO) between servers or clusters; unlimited in Datacenter, one 2 TB volume in Standard.

Automatic site failover in stretch clusters; Azure Site Recovery recovery plans for Hyper-V to Azure. Hyper-V Replica failover is manual or scripted.

Windows Server Backup for basic host backup; Microsoft Azure Backup Server is a separate product. No policy-driven VM backup built in.

No native immutable snapshots or ransomware detection; relies on third-party backup products.

Hyper-V is supported by all major backup vendors (Veeam, Commvault, Rubrik, Cohesity and others) through Resilient Change Tracking.

Azure Site Recovery replicates Hyper-V VMs to Azure with test failover and failback; Azure usage charges apply.

Full SDN stack in Datacenter: Network Controller (a Failover Cluster service in 2025), Hyper-V network virtualization, Software Load Balancer, gateways and SDN Multisite.

Network security groups (Datacenter Firewall) enforced in the Hyper-V switch, with tag-based segmentation and default deny-inbound policies in 2025.

Active Directory, JEA and Windows Admin Center RBAC; Microsoft Entra ID sign-in to Windows Admin Center in Azure through Arc. Workgroup clusters possible.

Secured-core server, TPM, Secure Boot, VBS and Credential Guard on by default; OSConfig security baseline with 350+ settings; hotpatching via Arc.

Windows Server 2025 is listed among Microsoft's Common Criteria certifications; Windows cryptographic modules go through FIPS 140 validation.

Windows Admin Center manages one cluster at a time; fleet management needs System Center VMM or Azure Arc (Windows Server Management enabled by Azure Arc).

Cluster-Aware Updating rolls OS updates across nodes; firmware and drivers come from OEM tools or Windows Admin Center extensions. Hotpatching via Arc cuts reboots.

Extensive PowerShell, WMI/CIM and DSC; REST through Windows Admin Center and Network Controller; Arc adds Azure APIs.

Health Service and cluster performance history for S2D, Windows Admin Center dashboards; Azure Monitor via Arc. No forecasting built in.

No self-service portal in the box; needs System Center VMM or third-party tooling.

Live migration, Failover Clustering HA restart, dynamic processor compatibility across CPU generations, and GPU-P live migration in 2025.

AKS on Windows Server exists but is being retired: 2019 node pools March 2026, 2022 node pools March 2027, the whole architecture March 2028. Microsoft points to Azure Local.

Azure Arc connects hosts to Azure: Update Manager, Machine Configuration, Windows Admin Center in Azure, ASR; some benefits require SA or pay-as-you-go.

Remote Desktop Services and third-party VDI run on Hyper-V; Azure Virtual Desktop session hosts are not supported on plain Windows Server hosts (Azure Local only).

GPU partitioning with HA and live migration, and Discrete Device Assignment. No packaged AI services.

No DBaaS; SQL Server runs in VMs or as failover cluster instances.

Manual build: install Windows Server, configure networking (Network ATC), run cluster validation and enable S2D via PowerShell or Windows Admin Center. Days for a first cluster.

Any server and components certified in the Windows Server Catalog; SDDC Standard/Premium qualifications recommended; the cluster must pass validation.

Two-node switchless clusters with USB or cloud witness fit branches, but there is no central fleet management without Arc or System Center.

Runs fully offline with perpetual licences, WSUS or offline updates. Pay-as-you-go and Arc benefits need connectivity.

Windows Admin Center VM Conversion extension (preview, free) migrates VMware VMs from vCenter 6.x-8.x with CBT sync; System Center VMM and partner tools are alternatives.

No free edition for production; a 180-day evaluation is available.

Licences move to any certified hardware; with SA, Azure Hybrid Benefit applies them to Azure VMs and Azure Local.

Separate calls to Microsoft for software and to the OEM for hardware, unless an OEM resells Windows Server with its own support.

Microsoft Unified Enterprise: critical response within one hour for products other than Azure.

Very large Windows Server and Hyper-V skills base, broad hardware certification, and support from all major backup and management vendors.

Standard VHDX format, perpetual licences, no cloud dependency and any certified hardware; tooling is Microsoft-specific.