Azure VM Increase Disk Size Without Disrupting Service

Increasing the disk size of an Azure VM without disrupting service is a delicate process that requires careful planning.

Azure VMs can have up to 32 disks attached, with a maximum size of 4 TB per disk.

To increase disk size without disrupting service, you'll need to detach the disk, resize it, and then reattach it.

This process can be automated using Azure PowerShell or CLI, making it easier to manage multiple VMs.

Azure provides a built-in feature to resize disks without downtime, but it's only available for Premium Storage disks.

For your interest: Increase Size of Text in Html

To increase the disk size of your Azure VM, you can update both the operating system and resize any data disks attached to it, making the disk size larger. However, there are some important factors to consider first.

You can only increase the size of the disks, and once allocated that new size can't be decreased. The maximum allowed is 4,095 GB for OS disks, but it's possible to expand the VHD blob beyond that size.

See what others are reading: D8_v3 Vm Size Azure

To resize a VM disk in Azure, it's a two-step process. First, you need to change the disk size itself, and then make the disk available in the operating system so that applications hosted in the VM can start using the additional capacity.

Here are the steps to increase the disk size:

Note: The new size should be greater than the existing disk size.

You can only increase the size of the disks, and once allocated that new size can't be decreased. This means you'll need to plan ahead and ensure you're not going to need a smaller disk size in the future.

The process of increasing disk size is a two-step process. First, you need to change the disk size itself, and then you need to make the disk available in the operating system so that applications can start using the additional capacity.

You can resize a VM disk in Azure via the Azure Portal, Azure CLI, or Azure PowerShell. The Azure Portal is a user-friendly interface that allows you to easily manage your resources.

A different take: Management Azure Portal

Here are the limitations to consider when increasing disk size:

If you need to expand a data disk without deallocating your VM, there are some specific requirements to keep in mind. This feature is not supported for shared disks, and it's only available for data disks.

Recommended read: Azure Data Studio vs Azure Data Explorer

You'll need to expand the volume in the operating system to take advantage of the larger disk after expanding your data disks without deallocating your VM.

The maximum allowed size for OS disks is 4,095 GB, but you can expand the VHD blob beyond that size.

To expand the volume, you can use Diskpart or Disk Manager, which are available in Windows.

It may take a few minutes for registration to complete before you can start expanding the volume.

The new size should be greater than the existing disk size to ensure the expansion is successful.

Here are the general steps to expand the volume in the operating system:

Azure VM Disk Resize is a crucial process to increase the storage capacity of your virtual machine. You can only increase the size of the disks, and once allocated, the new size can't be decreased.

To resize a managed disk in the Azure portal, navigate to the virtual machine where you want to expand the disk, select Stop to deallocate the VM, and then go to Settings > Disks. Select the disk you want to expand and click on Size + performance to select the new size.

The maximum allowed disk size for OS disks is 4,095 GB, and it's possible to expand the VHD blob beyond that size, but the OS works only with the first 4,095 GB of space. You can see the updated disk size in the Settings > Disks section.

You can expand data disks without deallocating your VM, but this feature has some limitations. For Standard HDD, Standard SSD, or Premium SSD disks, if the disk is 4 TiB or less, you need to deallocate your VM and detach the disk before expanding it beyond 4 TiB.

For more insights, see: Detach Os Disk from Azure Vm

Here are the supported and unsupported disk types for expanding without downtime:

To confirm that the disk has been resized, connect to the VM through SSH and run the command to check the amount of disk space available on the filesystem. The output will show you the correct disk space, and you can confirm that the disk is usable with the new storage space size.

To resize a managed disk in Azure, you'll need to deallocate the virtual machine. This is because operations on virtual hard disks can't be performed with the VM running.

You can do this by stopping the VM, but stopping the VM with az vm stop doesn't release the compute resources. To release compute resources, use az vm deallocate.

The maximum allowed size for an OS disk is 4,095 GB, but you can expand the VHD blob beyond that size. The OS will only work with the first 4,095 GB of space.

Expand your knowledge: How to Change Virtual Network/subnet in Azure Vm

If your disk meets the requirements in expand without downtime, you can skip deallocating the VM.

Here are the steps to resize a managed disk in Azure:

You can also resize a managed disk in the Azure portal. To do this, navigate to the Virtual Machine where you want to expand the disk, select Stop to deallocate the VM, and then follow the steps to resize the disk.

The new size of the disk should be greater than the existing disk size. You can select the new size from the list of available sizes or type in a custom size.

If you have enabled LiveResize and your disk meets the requirements, you can skip deallocation or stopping of VMs. However, you may experience a message saying "Changes to the disk size can be made only when the disk is unattached, or the managing virtual machine(s) are deallocated (Stopped)".

Classic VM SKU support can be a bit tricky, especially when it comes to expanding disks without downtime. If you're using a classic VM SKU, it might not support expanding disks without downtime.

To determine which VM SKUs support this feature, you can use a PowerShell script. This script will help you figure out which SKUs are compatible with expanding disks without downtime.

Unfortunately, not all classic VM SKUs support this feature, so it's essential to check before attempting to expand your disks.

Classic VM SKU Support is a bit tricky, but don't worry, I've got the lowdown.

If you're using a classic VM SKU, it might not support expanding disks without downtime.

You can use a PowerShell script to determine which VM SKUs support expanding disks without downtime.

Classic VM SKUs are a legacy option that might not have all the bells and whistles of newer SKUs.

The PowerShell script is a quick and easy way to check which SKUs are compatible with expanding disks without downtime.

It's worth noting that not all classic VM SKUs will support expanding disks without downtime, so it's essential to check before attempting to expand a disk.

Recommended read: Azure Vm Agent Is Not Ready

Ultra disks and Premium SSD v2 disks have some unique limitations when it comes to expanding them.

You can't expand a disk while a background copy of data is also occurring on that disk, like when a disk is being backfilled from snapshots. This can cause issues with the resizing process.

Allow up to 10 minutes for the correct size to be reflected in Windows VMs and Linux VMs. For Linux VMs, you must perform a Linux rescan function, while for Windows VMs that don't have a workload, you must perform a Windows rescan function.

The rescan process can be done immediately, but if it's within 10 minutes, you might need to rescan again to display the correct size. This is especially important for Windows VMs without workloads.

Here's a quick rundown of the Ultra disk and Premium SSD v2 limitations:

Keep in mind that Ultra disks and Premium SSD v2 disks have specific requirements for expansion, so be sure to follow the guidelines carefully.

To confirm that the disk has been resized, you'll need to check the filesystem. This can be done by connecting to the VM through SSH and running a command to show the amount of disk space available.

The command to run is not explicitly stated, but the output should show the new disk size, which in this case is 4,095 GB for OS disks. This is the maximum allowed size for OS disks.

You can also use the fdisk command to verify the new disk size. This command will show you the disk model, units, sector size, and disk identifier, among other things.

To rescan the disk and update its size, you can insert a 1 character into the rescan file for the device. This will trigger a rescan of the disk and update its size.

Here's a step-by-step guide to rescan the disk and update its size:

Note that the disk identifier may change if a different disk device was resized.

Azure VMs can be increased in disk size, but the availability of this feature depends on the region you're in.

Not all regions support increasing the disk size of Azure VMs.

You can check the availability of this feature in your region by checking the Azure documentation.

The maximum disk size that can be increased varies by region, ranging from 4 TB to 32 TB.

In the US, for example, the maximum disk size that can be increased is 32 TB.