We want to convert to managed disks in our azure virtual machines. We first need to convert the availability set to managed. During the conversion of the availability set is downtime expected?
Azure availability set has two SKUs.
use managed disks(aligned)
not use managed disks(classic).
If you migrate availability set to a managed availability set, there is no downtime for availability set migration. After you click convert button, you will begin to migrate the availability set.
After your availability set has been changed to managed type in the overview in the availability set portal. The VMs in this availability set is still using unmanaged disks, you can change unmanaged disks to managed disks for these VMs.
However, the conversion from unmanaged disks to managed disks requires a restart of the VM. You could refer to this official doc: Convert a Windows virtual machine from unmanaged disks to managed disks
Related
I have a AvailabilityZone set to my deployed VMSS, i would like to know how can i add and change AvailabilityZone to my current vmss but i cant find any option to do so.
I would really appreciate any inputs
Change the Availability Zone Sets
You can't add an existing VM to an availability set after it's created. VMs must be created within the availability set to make sure they're correctly distributed across the hardware. A VM can only be added to an availability set when it is created. To change the availability set, you need to delete and then recreate the virtual machine.
Please refer to the below documents for more information :- https://learn.microsoft.com/en-us/azure/virtual-machines/windows/tutorial-availability-sets
https://learn.microsoft.com/en-us/azure/virtual-machines/windows/change-availability-set
I am trying to provision Azure Virtual Machines to the same availability set one after the other. I see this error when trying to a provision in Australia East.
Provisioning failed. Allocation failed. Please try reducing the VM size or
number of VMs, retry later, or try deploying to a different Availability Set
or different Azure location.. AllocationFailed
This error means you are try to adding a big size VM to the Availability set, the VM size bigger than other VMs, that host does not support this VM size.
We should stop all the VMs in the availability set. Then add this new VM to it, then start the other VMs.
Here a blog about add VM to Azure availability set, please refer to it.
Update:
Please try to create new VM and at the same time to create Availability set, like this:
Can someone tell me the main benefits and differences between Managed disks and Unmanaged disks, various pros and cons of the managed and unmanaged disk and how best can I use this?
I would like to highlight some of the benefits of using managed disks:
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.
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.
Refer Azure Managed Disks Overview for more details.
Essentially, Managed Disks are easier to use because they don't require you to create a storage account. I think Azure still creates one, but this detail is hidden from you.
The benefit of not having to manage a storage account is that storage accounts have limits, like max IOPS, so that if you place too many disks in a storage account, it is possible that you will reach the IOPS limit. Azure takes care of this for you.
If you have VMs in an Availability Set, Azure will make sure that disks are on different "stamps" ensuring that disks are spread out so that you don't have a single point of failure for the disks.
As for a Con, I've encountered two (but there are probably more):
When taking snapshots they are Full Snapshots, not incremental, so
this adds to storage cost.
If you are setting up a Disaster Recovery between two Azure regions, using Recovery Services, managed disks are not yet supported.
Managed disk for Azure site recovery is now supported
Managed and unmanaged drives in Azure are different concept.
Unmanaged approach treat the drive as a service provided under storage account, you can use this "service" connecting it to your VM but from management perspective is completelly different entity.
Contrary to this approach managed drive is a HDD you connect to your VM, storage account behind it is managed by Azure, so you should get appropriate performance for your disk size. In fact because VMs have there own IOPS limits associatied with hardware profile size just resizing the disk will generally doesn't provide you better performance.
Since managed drives are newer and more "sophisticated" service they are also more expensive.
If you are interested in this topic I did quite complete comparison based on options available over az command line options here. There is also nice practical differences summary here
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
When creating a VM in Azure, you have the option of setting an Availability Set and Fault/Update domain. I have some VMs where I need to set the Availability Set and another set of VMs where I need to update the Fault/Update domain.
As far as I can see, this isn't available with the new Resource Group-based Virtual Machines and cmdlets, thus this previous post isn't applicable. Without recreating the VMs, what is the proper way to set these resources?
Because availability set membership determines which stamp (cluster) a VM will be created in, it isn't possible to configure the availability set after the machine is deployed.
The simplest solution would be to delete the VM, while retaining the disks, then create your availability set and create and add new VMs with the existing disks.
We have SQL Sever setup on A-series virtual machines. We are wanting to upgrade to the D-series virtual machine. Is it as simple as just upgrading the VM in Azure and clicking save or are there any other things I need to watch out for? I have heard of people having issues upgrading due to the level not being available in the cluster that their Virtual Machines sit in.
The hardware infrastructure used for A series VM is not suitable for D series VM. It might be possible that the cluster where the VM is hosted, has the hardware configuration required for creating A series VM alone.
However if you would still want to change from A series to D series VM, you will have to export disks and create a new VM using the previously saved disks.
Going forward as a workaround: when you create your very first VM in your Cloud Service, be sure to specify one of the D-SERIES size even if you do not need it immediately. Doing this, your Cloud Service will be “tied” to a cluster that will support both A-SERIES (except A8/A9) and D-SERIES, then for all the future VMs contained in the same Cloud Service. Now, you can create additional A-SERIES VMs and mix together in the same Cloud Service. If you do not need the first D-SERIES VM, you can now safely delete it.
If the D-series machines are not available due to the cluster, you can always delete the vm (preserve the disks) and create a new VM of the D-series and attach the existing disks to that system.
When you create the new VM, choose the option to 'create from template' and the select your OS disk from the 'My Disks' section. Then attach all the data disks to the VM once it's provisioned.