Azure Disks offers different performance tiers to match your application needs. High-performance, low-latency disks can be attached to Azure VMs for your I/O-intensive workloads. The following are the performance tiers in Azure Disks:
- Standard HDD: Offers the lowest cost and is backed by the HDD drives. This is ideal for disks that require fewer I/O operations such as backup storage. The maximum IOPS is 2,000, and the maximum throughput is 500 MB per second.
- Standard SSD: Offers lower latency compared to Standard HDD as these drives are using SSDs under the hood. This is ideal for web servers and medium I/O-intensive workloads. The maximum IOPS is 6,000, and the maximum throughput is 750 MB per second.
- Premium SSD: Excellent choice for production and I/O-intensive workloads. As the name suggests, these disks are also using SSDs; however, they are faster than Standard SSD. The maximum IOPS is 20,000, and the maximum throughput is 900 MB per second.
- Ultra disk: Perfect for transaction-heavy workloads such as SAP HANA, SQL, Oracle, etc. This offers massive IOPS up to 160,000 and a maximum throughput of 2,000 MB per second.
All tiers except Ultra disk offer a maximum disk size of 32,767 GB; on the other hand, Ultra disk can support up to a maximum value of 65,536 GB. The availability of Ultra disk is limited to certain regions and VM sizes. Some of the supported sizes include ESv3, Easv4, Edsv4, Esv4, DSv3, Dasv4, Ddsv4, Dsv4, FSv2, LSv2, M, Mv2, HBv2, HB, HC, NDv2, ND, NC_T4_v3, NCv2, NCv3, NVv3, and NVv4. Also, Ultra disks are available only as data disks, not as OS disks. The limitation of Ultra disk is covered here:
https://docs.microsoft.com/en-us/azure/virtual-machines/disks-types#ga-scope-and-limitations
Refer to this document before you plan to use Ultra disk. Now you will learn about how the disks are classified based on management.
Management
Based on the level of management, disks can be categorized as managed disks and unmanaged disks. Behind the scenes, when you create a disk, it gets stored inside an Azure Storage account. The classification you are about to learn is solely dependent on who manages this underlying storage account. Let’s understand the differences between these two.
Managed Disks As the name suggests, the disks are managed by Microsoft, and you don’t have to create any storage accounts to work with managed disks. The encryption, recovery plan, and control of the storage account are controlled by Microsoft, and you will not have any control over these factors. Microsoft recommends going with managed disks in all possible scenarios. Since you don’t manage the storage account, the storage account limits don’t apply, and you can have up to 20,000 disks per region.
Unmanaged Disks In unmanaged disks, you need to create the storage account that will be used to store the disk. Since you created this storage account, you will have complete control over the storage account and all the contents of the storage account. Here, you need to take care of the encryption, data recovery, etc.
Operating System
Azure supports various OS images that can be installed into the virtual machine. The list includes several versions of Windows and popular distros of Linux. You need to select the OS wisely as it will directly impact your billing. The reason for this is if you are selecting a Windows-based OS, then you will be charged for the license as well. So, it’s better to look at different options before you commit to the purchase.
In addition to the popular Windows and Microsoft-endorsed Linux distros, you have customized images available in Azure Marketplace. For example, if you would like to set up a WordPress site, then you need to deploy a Linux VM and install all the dependencies such as Apache, PHP, and MySQL. However, if you check Azure Marketplace, there are preconfigured images available for WordPress that you can directly use and avoid the hassle of configuration.
Nevertheless, if you can’t find the operating system that you are looking for, then you can bring your own virtual image to Azure that can be used to deploy virtual machines. If you are planning to bring your own image, note that Azure supports only 64-bit operating systems.
Now that you are familiar with the factors that need to be considered for the virtual machine planning, let’s go ahead and deploy some virtual machines.