what is the difference between managed disk and unmanaged disk?

Navin Prasad Kumar 61 Reputation points

When you create the disks, you will have two options one is unmanaged disks and the other one is managed disks. I want to know about the two things.

Azure Disk Storage
Azure Disk Storage
A high-performance, durable block storage designed to be used with Azure Virtual Machines and Azure VMware Solution.
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  1. Sumarigo-MSFT 40,886 Reputation points Microsoft Employee

    Azure Storage service is yet to be migrated to Q&A. Please post your question directly on the MSDN forum for the service (Azure Storage forum)

    We are actively working to onboard all services. We will make a public announcement once complete.
    Thank you for your patience as we evolve the Q&A platform

    However, I would like to highlight some of the benefits of using managed disks

    Managed Disks:
    The managed disk provides enhanced manageability and high availability which provides the following features.

    Simple - Abstracts underlying storage account/blob associated with the VM disks from customers. Eliminates the need to manage storage accounts for IaaS VMs.

    Secure by default – Role based access control, storage encryption by default and encryption using own keys.

    Storage account limits do not apply – No throttling due to storage account IOPS limits
    Big scale - 20,000 disks per region per subscription.

    Better Storage Resiliency - Prevents single points of failure due to storage Supports both Standard and Premium Storage disks

    Unmanaged Disks:

    Less availability: Unmanaged disks do not protect against single storage scale unit outage
    Upgrading process is complex: If you want to upgrade from standard to premium on unmanaged disks, process is very complex.

    Apart from this unplanned downtime, security is the downsides of the unmanaged disks. However, Cost differences between managed and unmanaged are based on your workload use case

    • Simple and scalable VM deployment: Managed Disks will allow you to create up to 10,000 VM disks in a subscription, which will enable you to create thousands of VMs in a single subscription.
    • Better reliability for Availability Sets: Managed Disks provides better reliability for Availability Sets by ensuring that the disks of VMs in an Availability Set are sufficiently isolated from each other to avoid single points of failure.

    Highly durable and available

    Granular access control: You can use Azure Role-Based Access Control (RBAC) to assign specific permissions for a managed disk to one or more users. Managed Disks exposes a variety of operations, including read, write (create/update), delete, and retrieving a shared access signature (SAS) URI for the disk.

    Azure Backup service support: Use Azure Backup service with Managed Disks to create a backup job with time-based backups, easy VM restoration and backup retention policies
    6.Are unmanaged disks still supported: Yes. Both support unmanaged and managed disks. We recommend that you use managed disks for new workloads and migrate your current workloads to managed disks.

    There is also nice practical differences summary here

    Managed Disks = are managed by Microsoft Azure and you don't need any storage account while created new disk. Since the storage account is managed by Azure you do not have full control of the disks that are being created.

    Un-managed Disks = is something which requires you to create a storage account before you create any new disk. Since, the storage account is created and owned by you, you have full control over all the data that is present on your storage account. Additionally, you also need to take care of encryption, data recovery plans etc.

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  1. Debleena Chakraborty 51 Reputation points

    Can we encrypt Unmanaged Disk using Azure Disk Encryption?

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  2. George Chrysovalantis Grammatikos 386 Reputation points MVP

    Hi @Navin Prasad Kumar ,

    Managed disks became known after the ARM was introduced. With managed disks, the disks management is more simplified than the unmanaged. Also, you can deploy cloud-scale VM scale sets more easily.

    Unmanaged disks are managed by Microsoft Cloud Services. In this case, you have a storage account and under this account one or more blobs (e.g vhd's).

    For unmanaged disks, there is a capacity limit of 500 TB per Storage Account.

    More details you can find in the link below :

    Introduction to Azure managed disks

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  3. Armand Brunelle 491 Reputation points

    Hi @Navin Prasad Kumar ,

    I would suggest paying attention with the cloud and Storage

    You should do some basics lessons maybe prior to this

    A lot of web site right now offer free storage, but you need to be careful about it... :)

    2 people found this answer helpful.
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