Linux VM OS Disk

[tamirkamara]

Description

As a Researcher
I want to have access to more disk space in Linux VM
So that I could store data in the VM for faster processing

[TonyWildish-BH]

@tamirkamara, a few questions if you don't mind:

• Is the motivation purely to have something faster than the shared storage? If so, is there any option to specify a performance tier for the shared storage instead, which might be simpler?
• Is this intended to be a shared disk, among any/all Linux VMs, or just per VM?
• If it's per VM, is there any reason not to simply increase the size of the system disk, letting the user specify the size, and perhaps the performance tier?
• Is there any requirement for Windows VMs to have the same performant disks?

[marrobi]

Maybe initially we do OS disk? Think that is a quick win, and I've hit this before. @tamirkamara should we create a new issue for this, or I can reword this one.

variable "os_disk_account_type" {
  description = "The type of storage account to use for the OS disk."
  type        = string
  default     = "Standard_LRS"

  validation {
    condition = contains(["Standard_LRS", "Premium_LRS", "StandardSSD_LRS", "UltraSSD_LRS"], var.os_disk_account_type)
  }
}

variable "os_disk_size" {
  description = "The size of the OS disk in GB."
  type        = number
  default     = 64

  validation {
    condition = contains([64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32767], var.os_disk_size)
  }
}

Need to prevent downsizing, not sure how that can be done.

[tamirkamara]

@TonyWildish-BH the motivation is mainly to allow more software to be installed on the VM. Not need to share with other VMs.
Indeed OS disk size is easier for this, however as pointed out earlier by Vijay, every image has a different default OS disk size so setting something below that might cause a problem.

[TonyWildish-BH]

thanks for the clarification, @tamirkamara. In that case, maybe this ticket should be renamed to 'System Disk', not 'Data Disk'?

I'd simply set a minimum value, say 50GB for Linux, 150GB for Windows, which is above the default OS sizes I've seen so far, and allow any value above that. I don't see the point in restricting to an enumerated set of values.

[marrobi]

There needs to be a minimum size, also maximum, also get billed at set size increments - https://learn.microsoft.com/en-us/azure/virtual-machines/disks-types#ultra-disk-size hence a drop down of choices might be the best option.

[TonyWildish-BH]

There needs to be a minimum size, also maximum, also get billed at set size increments - https://learn.microsoft.com/en-us/azure/virtual-machines/disks-types#ultra-disk-size hence a drop down of choices might be the best option.

fair enough, thanks!

[marrobi]

Not tested, but let copilot do some work - #4334

If someone is able to give it a test, or even pick up the PR and finish off, that would be great.

Might need to look at how to prevent reduction in disk size, or what happens if try to reduce.