Home > Storage > PowerFlex > White Papers > Dell APEX Block Storage for Azure: SQL Server 2022 Multi-Subnet Failover Clustering Deployment and Resiliency > Logical architecture
The logical architecture described in this section shows the deployment of a three node SQL Server 2022 multi-subnet failover cluster on Windows Server 2022 on a two-layer Dell APEX Block Storage configuration - SQL Server 2022 Node 1 in AZ-1, SQL Server 2022 Node 2 in AZ-2, and SQL Server 2022 Node 3 in AZ-3. SQL Server setup classifies this configuration as a multi-subnet cluster. The APEX Block Storage deployment across three AZs offers increased resiliency and availability.
The following Figure 3 represents the two-layer APEX Block Storage system using the Azure VMs local NVMe disks.
Figure 3. Logical architecture of WSFC and SQL Server on APEX Block Storage using Azure VMs local NVMe disks.
In each AZ, two SDS are installed on Standard_F48s_v2 Azure VM instance with the Linux SLES AMI. The Azure VM instances that are deployed by APEX Block Storage in Azure are backed by Azure managed disk drives. The Azure disks are locally attached at the Instance level. The six NVMe disks attached to APEX Block Storage SDS instances are configured into a single protection domain. A single storage pool is created, using all the storage devices available within the protection domain.
The APEX Block Storage volumes that are created from the APEX Block Storage pool are mapped to Azure VM compute instances running APEX Block Storage SDC services. The APEX Block Storage volumes mapped to instances are used to create the file system to host the databases.