Resize Azure 1 TB Unmanaged Premium storage to 4 TB storage

Question

Good day

We currently have 16x1TB Unmanaged premium storage disks on a Standard DS4 v2 (8 vcpus) in 1 storage pool.

For cost efficiency we would like to rather make use of 4x4 TB premium disks since it works out cheaper and then decrease the size to a DS3v2 (4 vcpu) (Which will be a reboot).

I can temporarily increase the DS4 v2 to DS5 v2 to allow me to add more disks and then add the 4x4TB disks but how am I going to move over all the data without affecting the system / downtime.

In the guest OS the 16 Drives are in 1 storage pool.

Also when I resize the VM back what will stop it from not removing the attached disks since it no longer supports the amount of disks?

Is there anyone that can give me pointers on what I should be looking at to achieve this?

http://prntscr.com/hxjmh8 - disk layout

Answer 1

You cannot resize an existing disk so you will need ot add the new disks, move the data and then remove the old disks. This is quite likely going to result in downtime.

I don't know how you are configuring your disks inside your VM. If you are using Windows and using storage spaces then you could look at adding the new disks to the existing pool and then removing the old ones, this should move the data around for you.

If your not using storage spaces then you are most likely looking at a data copy.

Answer 2

I can temporarily increase the DS4 v2 to DS5 v2 to allow me to add more disks and then add the 4x4TB disks but how am I going to move over all the data without affecting the system / downtime.

If you want to resize VM's data disks, you need stop your VM firstly. It needs some downtime.

If you resize a VM to a smaller size, you need unattach disks firstly.

So, I suggest you need backup your data firstly. Then stop your VM, resize data disk to 4096GB. You could use Power Shell to do this. See this link.

$vm.StorageProfile.DataDisks[0].DiskSizeGB = 4096

You also have another solution. Unattach your all disks all and attach four 4TB disks. Unattch and attach disks don't need stop your VM, it will reduce downtime. But resize VM need some downtime.