AZ-120 Sample Questions & Answers

The Azure Fence Agent (fence_azure_arm) is the Microsoft-recommended fencing mechanism for Pacemaker clusters on Azure. It interacts directly with the Azure Resource Manager API to power off a faulty node, providing a reliable way to prevent split-brain scenarios. SBD with a shared iSCSI target is a common on-premises solution but requires a third server acting as the iSCSI target, which adds complexity and a single point of failure in Azure. SBD with Azure shared disks is possible but the Azure Fence Agent is simpler and more robust. fence_scsi is not applicable in a standard Azure VM environment.

Write Accelerator should only be enabled for the disks that host the SAP HANA transaction log (/hana/log) volume. It is specifically designed to improve write latency for log files. Enabling it on the data volumes (/hana/data) is not recommended and provides no benefit, as these volumes have a different I/O pattern that is not optimized by Write Accelerator.

Given the large data size (10 TB) and the limited internet bandwidth (100 Mbps), an online transfer using AzCopy or Azure Storage Explorer would be extremely slow and might not complete within the required timeframe. Azure Data Box is a physical appliance that Microsoft ships to the on-premises datacenter. You can copy the backup files to the device and then ship it back to an Azure datacenter, where the data is uploaded to Blob Storage. This offline transfer method is ideal for large-scale data migration with network constraints. ASR is used for VM replication, not for transferring backup files.

The standard SAP best practice for HANA storage layout is to separate the data, log, and shared volumes onto different disks or logical volumes. This is done to isolate the different I/O patterns: /hana/data for high-throughput reads and writes, /hana/log for low-latency sequential writes, and /hana/shared for binaries and configuration files. /usr/sap is typically placed on a separate disk as well, but /hana/data, /hana/log, and /hana/shared are the three core HANA-specific volumes that must be separated for performance and operational reasons. The root filesystem (/) and swap space are also on their own volumes.

Azure Center for SAP solutions (ACSS) includes a 'Quality Checks' feature. This feature runs a series of validations against the deployed infrastructure (VMs, storage, networking) to ensure it meets SAP on Azure best practices before proceeding with the SAP application installation. This helps prevent common configuration errors and ensures a more stable and performant final system. Cost Analysis is for financial tracking, Software Installation is the subsequent step, and Monitoring is for post-deployment operations.

A Proximity Placement Group (PPG) is an Azure logical grouping capability used to ensure that Azure compute resources are physically located close to each other, resulting in the lowest possible network latency. This is the primary mechanism for colocating latency-sensitive components of an SAP system, such as the database and central services tiers. Availability Sets and Zones are for high availability and distribute VMs across different fault/update domains or physical datacenters, which can increase latency.

Azure Private Link provides private connectivity from a virtual network to Azure PaaS services (like SAP BTP), customer-owned, or Microsoft partner services. It maps the service to a private endpoint in your virtual network, ensuring that traffic between your VNet and the service travels over the Microsoft backbone network, avoiding exposure to the public internet. This is the standard and most secure method for integrating Azure VNets with SAP BTP privately. VNet peering is for connecting two VNets. ExpressRoute is for hybrid connectivity. A VPN gateway would typically route traffic over the internet unless configured with ExpressRoute.

To calculate the composite SLA for services in series, you multiply their individual SLAs. In this architecture, a user request must successfully pass through the Standard Load Balancer AND be serviced by the available application servers in the Availability Set. Therefore, the composite SLA is the product of the Availability Set SLA and the Load Balancer SLA. Calculation: 0.9995 * 0.9999 = 0.99940005, which is approximately 99.94%.

The authoritative source for SAP HANA certified infrastructure, including Azure VMs, is the SAP Certified and Supported SAP HANA Hardware Directory. This directory, maintained by SAP, lists all certified hardware and cloud providers, along with the specific VM SKUs, memory sizes, and their corresponding SAPS ratings. This is the official reference for ensuring compliance and supportability for SAP HANA on Azure. The Azure documentation provides guidance but points to the SAP directory as the source of truth.

The --location parameter in the Azure CLI az ppg create command requires a valid Azure region name, such as westus2. A proximity placement group is a regional resource, and its location must be specified upon creation.