Azure Disk Storage

Azure uses disks to store operating systems, applications, and data. Virtual machines have two disks at the very least- a Windows operating system disk and a temporary disk. Operating system disks and images are stored as virtual hard disks (VHDs) in Azure storage accounts. In Azure, VHDs are .vhd files stored as page blobs within an Azure storage account. Additionally, a virtual machine can have one or more data disks that are stored as VHD files.

Disk Temporary: It is associated with the virtual machine that is provisioned from the underlying hardware. Hence, it is not stored in a storage account. There will be a copy of it stored on the server's underlying hardware.

Types of Disk

Different kinds of disks that are offered by Azure:

Disks that are unmanaged: These are traditional disks that have been used by virtual machines. By creating these disks, we can create a storage account and specify that account when we create the disk. There must not be too many disks in the same storage account, which will result in the VMs being throttled.

Managed disks: It takes care of the creation and management of storage accounts in the background for us, ensuring that we are not concerned about the storage account's scalability limits. Azure creates and manages the disk for us based on the disk size and performance tier (standard / premium).

HDD disks are the cheapest. Replication can be local or geo-redundant with primary and secondary data centers.

Standard SDD disks provide the same kind of performance and reliability as HDDs, but are designed to address the same kinds of workloads. It is suitable for applications like web servers that don't require high IOPS on disk.

VMs running I/O-intensive workloads will benefit from premium SSD disks, which are backed by SSDs and offer high-performance and low-latency disk support. Premium SSD disks are designed primarily for production and database servers. If we intend to host a database on a specific server, the premium SSD will be a good choice.

Our previous unmanaged disks should be converted to managed disks according to Microsoft recommendations for new VMs.

Disks backup

With a Virtual Machine, we need to back up the OS disk and the data disk regularly so that in case of data loss, we can recover the data.

Azure provides the Azure backup service, which you can install as a backup extension on a particular VM and the extension based on the frequency you specified will take the snapshot off OS disk, and the data disk. And also, at different levels, so we can bring application-consistent snapshots, file consistent snapshots, and these snapshots will be moved into recovery service vault. That's where these snapshots will be stored. In case if something goes wrong with our VM or any particular data center is gone. We can still recover the virtual machine using these snapshots, and if we want to have a geo-redundant ability, then we can have this recovery services vault located in another region.

If our VM is located in northern Europe, then our recovery service vault can be located in western Europe. In that way, we can protect our workloads against regional failure also.