Azure VM Rightsizing: 5 Steps to Cut Costs
Learn how to effectively rightsizing Azure VMs to reduce costs while maintaining optimal performance through practical, step-by-step guidance.
Want to save money on your Azure VMs? Start by rightsizing. Many organisations overpay for virtual machines (VMs) that don’t match their workload needs. Rightsizing ensures you’re only paying for the resources you use while maintaining performance.
Key Steps to Get Started:
- Monitor Performance: Track CPU, memory, storage, and network usage to identify over- or under-provisioned VMs.
- Identify VMs to Resize: Spot VMs with low usage (overprovisioned) or performance issues (underprovisioned).
- Choose the Right VM Size: Match VM types (e.g., B-series for low CPU tasks, E-series for memory-heavy apps) to workload demands.
- Make Changes Safely: Back up data, test in non-production environments, and monitor performance during resizing.
- Review and Adjust: Regularly check performance and costs to ensure continued efficiency.
Quick Tip:
Use Azure tools like Azure Monitor, Azure Advisor, and Cost Management to track metrics, get cost-saving recommendations, and automate alerts for better cost control.
By following these steps, you can reduce costs without compromising performance. Ready to optimise your Azure VMs? Let’s dive in.
Advisor Clinic: Rightsize your Azure Virtual Machines
Step 1: Measure Current VM Performance
Before resizing your virtual machines (VMs), it's essential to gather detailed performance data. This ensures you make informed decisions and avoid costly mistakes. By focusing on specific metrics, you can better align your VM resources to actual needs.
Key Performance Metrics
Here are the main areas to monitor:
CPU Usage
- Average usage (aim for 50–75% during peak times)
- Patterns of peak utilisation
- Number of active processor threads
Memory (RAM) Performance
- Difference between available and allocated memory
- Page file usage levels
- Signs of memory pressure
Storage Performance
- Input/output operations per second (IOPS)
- Disk queue length
- Read/write latency
- Remaining storage capacity
Network Performance
- Bandwidth consumption
- Network latency
- Packet loss rates
Azure Monitoring Tools
To track these metrics effectively, you can use Azure's built-in monitoring tools:
Azure Monitor
- Provides real-time performance insights
- Offers custom dashboards, alerts, and access to historical data
- Allows you to combine metrics for a detailed view
- Enables cross-VM performance comparisons
- Supports data export for reporting purposes
Suggested Monitoring Intervals
- CPU and memory: Every 5 minutes
- Storage: Every 15 minutes
- Network: Every 5 minutes
Setting Up Performance Monitoring
Follow these steps to configure your monitoring:
- Enable VM diagnostics in Azure.
- Set up Azure Monitor to track the key metrics.
- Configure alerts for critical thresholds.
- Review the data weekly during the first month.
- Adjust your monitoring parameters as needed.
Step 2: Find VMs to Resize
Check performance data to spot VMs that don't match their workload needs. Look at CPU, memory, disk I/O, and network I/O metrics to identify VMs that are either overpowered or struggling. This ensures that any changes you make are aligned with actual operational requirements.
Signs of Incorrect VM Sizing
- Overprovisioned VMs: If resource usage is consistently low, the VM likely has more capacity than needed. Downsizing can save costs.
- Underprovisioned VMs: High, sustained usage or bottlenecks suggest the VM can't handle the workload. Upsizing might be necessary for better performance.
Where to Start with Adjustments
Focus first on changes that save the most money with the least operational risk:
- Non-production environments: Development or testing VMs are a good starting point since resizing them carries less risk to business operations.
- Consistent usage patterns: VMs with steady resource usage that doesn't match their workload are prime candidates for resizing.
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Step 3: Pick the Best VM Size
Once you've identified which VMs need resizing, the next step is choosing the most suitable size. The goal is to strike the right balance between performance and cost by aligning resources with workload needs.
VM Types and Their Uses
Azure provides a variety of VM series, each tailored for specific workloads:
| VM Series | Ideal For | Common Use Cases |
|---|---|---|
| B-series | Low-CPU, burstable tasks | Development servers, small web servers |
| D-series | General-purpose tasks | Web apps, testing environments |
| E-series | Memory-heavy applications | Database servers, in-memory caching |
| F-series | Compute-heavy workloads | Batch processing, analytics |
| Ls-series | Storage-focused tasks | Large databases, data warehousing |
Once you've identified the right VM type, you can implement cost-saving measures to manage expenses effectively.
Ways to Lower VM Costs
Choose the Right Size
- Evaluate resource usage - if a VM consistently underuses its capacity, switch to a smaller size to save money.
- Match the VM's specifications to the actual demands of your workload.
Optimise VM Usage
- For workloads with variable performance needs, consider B-series VMs that offer burst capabilities.
- Set up automatic shutdowns for development environments to avoid unnecessary costs.
- Use reserved instances for workloads that are predictable and run over extended periods.
Step 4: Make Changes Without Disruption
Careful planning is key to making changes without affecting service availability or causing downtime for your applications.
Pre-Change Checklist
Before resizing a virtual machine (VM), ensure you’ve completed these key steps:
| Task | Description | Why It Matters |
|---|---|---|
| Backup Data | Create full VM snapshots | Protects against data loss |
| Schedule Window | Plan changes during off-peak hours (e.g., 22:00–04:00) | Reduces impact on users |
| Test Environment | Run the resize operation on a clone | Helps identify potential issues |
| Application Health | Check all dependencies and connections | Avoids unexpected failures |
| Resource Capacity | Confirm target host availability | Ensures migration success |
Steps to Resize a VM in Azure
Once everything is in place, follow these steps to resize your VM:
1. Prepare the Environment
Start by reviewing dependency documentation. Make sure the new VM size is available in your region and that your subscription has sufficient quota for the change.
2. Set Up Monitoring
Use Azure Monitor to track critical metrics such as CPU usage, memory utilisation, and network performance during and after the resize. This will help you catch any issues early.
3. Perform the Resize
- Log in to the Azure Portal.
- Select the VM you want to resize.
- Choose the new size and confirm the change.
- Monitor the progress through Azure’s feedback system.
4. Validate Performance
- Check that your application is functioning properly.
- Ensure all services are running as expected by reviewing performance metrics and testing connectivity.
- Confirm that users can access the application without issues.
Important: Always have at least two connection methods to the VM during resizing. This ensures you won't lose access if one connection fails.
For critical workloads, you might want to use Azure Site Recovery or a load-balanced setup. These options allow for staged migrations, helping you avoid any downtime.
Step 5: Track Results and Adjust
Once you've completed VM rightsizing, it's crucial to keep an eye on cost savings and performance improvements to ensure everything is running efficiently.
Regular VM Size Reviews
Set up a consistent review process to assess VM performance and costs. Here's an example schedule to help you stay on top of things:
| Review Area | Metrics to Track | Review Frequency |
|---|---|---|
| Performance | CPU usage, memory consumption, disk I/O | Weekly |
| Cost Analysis | Actual spend vs budget, cost per VM | Monthly |
| Capacity Planning | Resource usage trends, growth patterns | Quarterly |
| Optimisation Checks | Idle resources, usage patterns | Monthly |
Look at key metrics like CPU usage during both peak and off-peak times to see if adjustments are needed. Use cost tracking tools to stay within your budget.
Tools for Cost Tracking
Azure Cost Management + Billing provides several tools to help you monitor VM spending and spot areas where you can save:
-
Set Up Cost Alerts
Use cost alerts in Azure Cost Management to get notified when spending approaches your budget. This allows you to act quickly and make changes as needed. -
Leverage Azure Advisor
Azure Advisor analyses your VM usage and offers personalised recommendations. It can help you find:- Underused VMs that could be resized or consolidated
- Reserved instance opportunities for long-term savings
- Resources that can be powered down during non-business hours
-
Generate Custom Reports
Create reports tailored to your needs, focusing on:- Daily VM running costs
- Resource usage trends
- Cost breakdowns by department or project
- Actual savings compared to projections
Export these reports regularly to validate your cost-saving efforts and plan future optimisations. By continuously reviewing performance and cost data, you can identify VMs that still aren't sized correctly and make further changes, such as enabling automated scaling or switching to a different VM type.
For more tips on saving costs and improving efficiency in Azure, check out Azure Optimization Tips, Costs & Best Practices.
Conclusion: Next Steps for VM Cost Control
Keeping virtual machine (VM) costs under control requires consistent reviews and smart use of data-driven tools. Azure Advisor is a key resource, offering suggestions based on actual usage and spending patterns.
To build on regular performance reviews, consider these practical steps:
- Check Azure Advisor weekly for updated VM sizing suggestions.
- Track essential metrics, such as:
- Initial costs
- Savings achieved
- Performance metrics before and after adjustments
- Impact on workload efficiency
- Use Azure Monitor and Azure Advisor to regularly validate recent changes and ensure performance aligns with expectations.
For small and medium-sized businesses aiming to make the most of their Azure investment, combining Azure Advisor's insights with expert guidance from Azure Optimization Tips, Costs & Best Practices offers a well-rounded approach. This resource dives into cloud architecture, security practices, and performance improvements tailored for businesses scaling on Azure.
An iterative approach to VM rightsizing helps keep costs under control while maintaining top-notch performance. By following these strategies and leveraging Azure's tools, you can strike the right balance between efficiency and cost-effectiveness.
FAQs
How do I choose the right Azure VM size for my workload needs?
Selecting the optimal Azure Virtual Machine (VM) size for your workload involves evaluating a few key factors. Start by analysing your workload's performance requirements, such as CPU, memory, and storage needs. Next, consider the expected traffic patterns - whether they are consistent or vary during peak times. Azure provides tools, such as the Azure Advisor, to help assess and recommend suitable VM sizes based on your usage data.
By rightsizing your VMs, you can avoid over-provisioning resources, which can lead to unnecessary costs, while ensuring performance is not compromised. Regularly reviewing and adjusting your VM sizes is a best practice to maintain cost efficiency and scalability.
What potential risks should I be aware of when resizing Azure virtual machines, and how can I address them?
Resizing Azure virtual machines (VMs) can offer cost and performance benefits, but there are some risks to consider. Downtime is a key concern, as resizing often requires restarting the VM, which could disrupt services if not planned properly. Additionally, compatibility issues may arise if the new VM size doesn't support certain features or configurations of your current setup.
To mitigate these risks, schedule resizing during off-peak hours to minimise disruption and ensure critical workloads are not affected. Always verify that the new VM size is compatible with your applications, storage, and networking requirements before making changes. Regularly back up your data to prevent any loss during the resizing process. Careful planning and testing can help ensure a smooth transition while optimising your Azure costs.
How often should I review and adjust my Azure VM settings to optimise costs and maintain performance?
It’s a good practice to review your Azure virtual machine (VM) configurations at least quarterly or whenever there are significant changes to your workload or business needs. Regular reviews help ensure your VMs are not over-provisioned, which can lead to unnecessary costs, or under-provisioned, which may impact performance.
You should also monitor usage patterns through Azure Monitor or Cost Management tools. These can provide insights into how your resources are being utilised, making it easier to identify opportunities for optimisation. By staying proactive, you can achieve a balance between cost-efficiency and performance reliability.
