Operating System Disk:
Every virtual machine has one attached operating system disk. It’s registered as a SATA drive and labeled as the C: drive by default.
Each virtual machine consists of a temporary disk .The temporary disk is labeled as the D: drive by default and this is used for storing pagefile.sys. The size of the temporary disk varies, based in the size of the virtual machine. Data on the temporary disk is not fully secured as it can be lost during a maintenance event or when someone deploys a virtual machine.
A data disk is a Virtual Hard Disk that’s attached to a virtual machine to store application data, or other data you need to keep data disks are registered as SCSI drives and are labeled with a letter you choose. Each data disk has a maximum capacity of 4095 GB.
Anybody can add data disks to a virtual machine at any time. This is done by attaching the disk to the virtual machine. Attaching a data disk associates the virtual hard disk file with the virtual machines by placing a ‘lease’ on the VHD so it can’t be deleted from storage while it’s still attached.
Azure Storage is Microsoft’s cloud storage solution for modern data storage scenarios. Azure Storage offers a massively scalable object store for data objects, a file system service for the cloud, a messaging store for reliable messaging.
Azure Storage is:
- Durable and Highly Available
Types of Disks Storage:
Azure Disks are designed for the maximum availability. There are two performance tiers for storage that you can choose from when creating your disks—Standard Storage and Premium Storage. Also, there are two types of disks—Unmanaged and managed – and they can reside in either performance tier.
The most widely used storage accounts are standard storage accounts, which can be used for all types of data. Standard storage accounts use magnetic media to store data. It delivers reliable, low-cost disk support for virtual machines running latency-insensitive workloads. With Standard Storage, the data is stored on hard disk drives (HDDs).
There are two ways to create standard disks for Azure VMs:
- Unmanaged Disks: This is the original method where you manage the storage account used to store the VHD files that correspond to the VM disks. Unmanaged disks can be attached to any Azure VM size, including the VMs support attaching several standard disks, allowing up to 256 TB of storage per VM.
- Managed Disk: This feature manages the storage accounts used for the VM disks for us. There is no issue of placing the disks across multiple storage accounts in order to ensure our stay within the scalability limits for the storage accounts—Azure helps us by solving those problems.
Azure Premium Storage delivers high-performance, low-latency disk support for VMs with input/output (I/O)-intensive workloads. VM disks that use Premium Storage store data on solid-state drives (SSDs). To take advantage of the speed and performance of premium storage disks, you can migrate existing VM disks to Premium Storage.
Azure offers two ways to create premium storage disks for VMs:
- Unmanaged Disks: The original method is to use unmanaged disks. In an unmanaged disk, you manage the storage accounts that you use to store the virtual hard disk(VHD) files that correspond to your VM disks. VHD files are stored as page blobs in Azure storage accounts.
- Managed Disks: When you choose Azure Managed Disks, Azure manages the storage accounts that you use for your VM disks. Azure creates and manages the disk for us. Azure handles the placing of the disk in multiple storage accounts.