Key Considerations and Best Practices for Running Azure Virtual Machines and Services

Running a project locally versus deploying it to Azure cloud introduces several differences; understanding these helps prevent unnecessary problems.

1. Cost

During Azure usage, the designated contact email receives weekly reminders about remaining credit and expiration dates. You can also log into the billing portal at any time to view balance and should maintain sufficient funds based on actual consumption.

2. Data Storage in Virtual Machines

Azure VMs have two disk types: disks stored in Blob storage (persistent) and disks stored on the physical host (temporary). Blob disks are replicated three times locally and once off‑site, offering high availability. Temporary disks depend on the physical host and are cleared on reboot; therefore, important data should never be placed on the D: drive (temporary disk). Instead, attach a data disk for persistent storage.

Disk types for different Azure VM families:

Windows VM: C: (system) is a Blob disk, D: is temporary.

Linux VM: sda1 (root) is a Blob disk, sdb1 (/mnt/resource) is temporary.

3. Load‑Balancing Environment

Azure web sites, cloud services, and VMs all provide load‑balancing. Traditional load balancers often use session‑sticky mechanisms, but Azure’s cloud‑service and VM load balancers operate at the network layer and distribute requests round‑robin, requiring stateless back‑ends. For stateful applications, you can either share session data across servers (e.g., distributed cache, session persistence using databases, Azure Cache, or Azure storage) or configure a load‑balancing cluster on the VM (Microsoft’s MSOpenTech provides an automated IIS ARR configuration guide).

Web‑site services use IIS ARR, which natively supports session stickiness by adding an ARRAffinity cookie to responses, ensuring subsequent requests from the same user are routed to the same server.

4. What Are the Advantages of SSD Storage?

Microsoft introduced the D‑series VM family, offering more memory, CPU, and faster I/O. For I/O‑intensive workloads such as OLTP and NoSQL databases, SSD storage provides higher IOPS compared to magnetic disks, and D‑series VMs are about 60% faster than the older A‑series.

5. Difference Between Public IP (VIP) and Instance‑Level IP

Public IP (VIP) is associated with the cloud service that contains the VM. Accessing the service via the VIP goes through the load balancer, which forwards traffic to VMs based on ports.

Instance‑Level IP is directly assigned to a VM, allowing direct connection to the VM and supporting multiple ports and dynamic port allocation.

6. When Does the Billing Clock for a Reserved IP Start and Stop?

The billing clock for a reserved IP begins two hours after the IP is allocated, giving time for assignment. It stops when the reserved IP is deleted.

7. How to Guarantee SLA?

Deploying two or more role instances across different fault and upgrade domains ensures that internet‑facing roles achieve at least 99.95% availability. See the Azure SLA details and information on upgrade and fault domains for more specifics.

8. About Azure Storage

When building applications, consider storage costs such as bandwidth, transactions, and capacity. Detailed pricing information can be found in the linked Azure storage cost article.

9. Effective Diagnostic Information

When a cloud‑deployed application encounters issues, diagnostic data from both the cloud and the host server help identify root causes. Refer to the provided MSDN article for guidance.

10. Best Practices for Various Services

(Content adapted from InfoQ.)