If you have deployed virtual machines on Azure, you must know that we need a storage account to store the VHDs for the virtual machine and based on the images/VHDs, we provision a VM.
With the old traditional deployment along with the hustle of managing the Storage account, there were few limitations as well :
- Only 40 disk per storage account and 20 storage account per subscription are there, so we can have a maximum of 20 *40 = 800 VMs per subscription with the old approach.
- With each Storage account, there comes a limitation of 20,000 IOPS limit.
Introducing Managed Disk
With Managed Disks, Microsoft is taking away the hustle of managing Storage Accounts on your behalf; you don’t need to create Storage Accounts for virtual machine disks anymore. You can deploy standard (HDD) or premium (SSD) Managed Disks, with LRS fault tolerance (3 copies in a single datacenter),GRS option is not yet supported though. This lifting is achieved when Azure manages the placement of the managed disks in the background to one or more storage accounts. You will not see the storage accounts anymore and only the disks which belong to the VMs are visible.
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Resolving the limitations
You don’t have to worry about the 20,000 IOPS limit of a storage account anymore; just deploy more virtual machines with Managed Disks, and Azure handles the placement of your disks.
If you are creating your own generalized images, then you don’t have to copy them to multiple storage accounts anymore – you simply store the image (a virtual hard disk) in a single storage account (as a blob) in each required region.
You can have up to 10,000 Managed Disks in a single Azure subscription – it’s 2,000 by default but you can have it increased by calling Microsoft support. If you are into on-demand scaling, then Virtual Machine Scale Sets (VMSS) can handle up to 1,000 virtual machines with Managed Disks.
Azure Storage manages how the disk size and I/O capacity are assigned to the Applications by load balancing data, which is based on the traffic generated by an app, so that the demand grows. Azure Storage adds the disk capacity, as required, while primarily, it is intended for Cloud apps, Azure Storage can also be used by the apps running on the local devices and On-Premises Servers. For high-performance workloads, the Preium Storage tier provides low-latency disk support for Azure-based VMs.
Microsoft has learned over the years from the client solutions and used best practices with the availability set to make sure to give you high availability. One disk is attached to one VM, which makes the availability much higher.
Summary
Managed Disks is the feature, where Microsoft is taking care of all the hassles of using a storage account by using best practices. It will give us more power and flexibility by removing the limitations of 20,000 IOPS per storage account. Also, with 20 storage accounts and 40 images in one storage account, it was a limitation, which is now resolved and you can have 10,000 Managed Disks in one Azure subscription.