Azure Migrate VM Assessment

Azure Migrate Discovery and assessment tool leverages the wealth of information gathered through the Azure Migrate discovery process to provide a comprehensive assessment of your workloads prior to migration to Azure. Assessments can be for Azure VM, Azure SQL, Web apps on Azure or Azure Vmware Solutions (AVS). This article provides an overview of Azure VM assessments.

The Azure VM assessment provides insights into the readiness of your servers for Azure compatibility and estimated monthly costs for compute and storage for running the servers in Azure. After setting up discovery, it’s recommended to wait at least a day before running a performance-based assessment.

Create an Assessment

 In "Assess" section of Azure Migrate dashboard you can create a new assessment by specifying the assessment name, target region, and assessment properties. VM sizing criteria maybe either “As on-premises” or “Performance-based” criteria. It is recommended to select performance-based over a representative period as this considers the VM utilization data to provide more accurate sizing.  Savings options include using Azure Reserved Instances or Azure Hybrid Benefit to optimize costs for long-term commitments. These options can provide significant savings on VM usage.

Define Assessment Scope

Specify the scope of the assessment by selecting the servers or VMs you want to assess for migration. You can choose specific servers or VMs, Server Group, or assess all discovered servers. I like to create groups of VMs that I have deemed suitable for migration based on the dependency analysis from the Azure Migrate discovery phase.

Configure Assessment Properties

Configure additional assessment properties, such as assessment duration, performance data retention period, and assessment frequency. These settings determine how long Azure Migrate collects data and how often it updates the assessment.

 Run the Assessment

 Once you've configured the assessment settings, initiate the assessment run. Azure Migrate will start collecting data from the discovered servers and analyzing it to provide migration recommendations. Several assessments can be run with different settings defined as necessary.

Review Assessment Result 

After the assessment run is complete, review the assessment results in the Azure portal. You'll find detailed reports that provide insights into the suitability of your on-premises environment for migration to Azure. These reports include recommendations for VM sizing, cost estimation, migration readiness, and dependency analysis.

Each assessment is assigned a "confidence rating" ranging from one (lowest) to five (highest) stars. It provides an indication of how confident Azure Migrate is in the accuracy of its recommendations and findings. Since assessments are point-in-time snapshots, it is recommended to recalculate the assessment to use the latest performance metrics data and thus increase the confidence rating.

Azure Readiness

Azure migrate identifies potential issues such as unsupported configurations (e.g., operating system, disk size) and provides readiness ratings: Ready for Azure, Ready with conditions, Not ready for Azure, or Readiness unknown. The detailed reasons provided for each rating along with recommendations for resolution helps pre-empt migration issues.

Azure Sizing

Appropriate sizing of Azure VMs is crucial for optimal performance and cost efficiency, and Azure Migrate simplifies this process by translating on-premises system CPU, disk, and memory metrics into Azure equivalents. Azure Migrate's recommendations for VM sizes based on CPU and memory utilization data can serve as a valuable reference point during the sizing process. It is important to maintain a balance between resource utilization and performance to avoid under-provisioning or over-provisioning while minimizing costs. Future growth, seasonal variations in workload demands and scalability requirements should also be considered.

The recommendations typically include specific Azure VM series that align with the compute, memory, and storage requirements of your workloads. Azure offers various VM series optimized for different use cases, such as general-purpose computing, memory-intensive applications, compute-intensive workloads, and more.

Some of the commonly recommended Azure VM series include:

1. General-purpose (D- series): These VM series offer a balance of compute, memory, and storage resources suitable for a wide range of applications and workloads.

2. Memory-optimized (E -Series): These VM series are designed for memory-intensive applications that require high RAM-to-CPU ratios, such as databases, analytics, and caching.

3. Compute-optimized (F-series): These VM series provide high-performance compute resources, making them ideal for compute-intensive workloads such as high-performance computing (HPC), gaming, and rendering.

4. Storage-optimized (L-series): These VM series are optimized for storage-intensive applications, offering high disk throughput and IOPS (input/output operations per second), making them suitable for databases, big data processing, and content delivery.

The CPU utilization %, indicates the % capacity that the CPU of the assessed server is operating at. This metric reflects how much of the CPU's processing power is currently being utilized by the workload running on the server. Some recommendations based on migration experience is as follows.

CPU Utilization	Recommendation
0%	Consider decommissioning server
1% - 30%	Consider reducing CPU cores
30% - 70%	Consider as-is sizing CPU cores
> 70%	Consider increasing CPU cores

 The memory utilization %, indicates how much of the available memory resources are currently being used by the workload running on the assessed server. Some recommendations based on migration experience is as follows.

Memory Utilization	Recommendation
0%	Consider decommissioning server
1% - 30%	Consider reducing memory
30% - 70%	Consider as-is memory
> 70%	Consider increasing memory

 Before proceeding with migration, you should validate the sizing recommendations and make adjustments if necessary. Azure Migrate allows you to fine-tune VM sizes based on your specific requirements or constraints.

Cost Analysis

Azure Migrate  offer estimations for compute and storage costs associated with running your workloads in Azure. However Azure Migrate doesn't directly provide detailed network cost analysis within it's platform. Network costs in Azure primarily depend on data transfer between Azure services, regions, and outbound data transfer to the internet. These costs are typically determined by Azure's pricing model for data transfer, which includes factors such as data volume and distance travelled.

The Azure Pricing Calculator should also be utilised to estimate the cost implications of different VM configurations based on CPU and memory sizing as well as network costs. This tool helps in making informed decisions by comparing pricing options and optimizing resource utilization.

Once assessment findings have been reviewed with stakeholders, then the migration planning phase can begin by grouping workloads based on dependencies and/or business priorities, scheduling migration waves, and identifying any prerequisites or dependencies that need to be addressed before migration. Azure Migrate Migration tools is then used to replicate VM data and workloads from on-premises to the appropriate appropriate Azure region, subscription, resource group and networking configuration.

After successful migration it is best to monitor the performance and health of the servers. The free tool, Azure Advisor provides useful cost saving proposals by recommending resizing to cheaper SKUs or commitment-based discounts such as Reservations and Azure Savings Plans.