Questions about storage solutions for VM

Question

Hello,
I'm trying to build a VM for the Azure Marketplace. My question are about storage solutions. The starting point is an E2as_v4 VM, which comes with about 32 GB for the OS plus 30 GB for data, which I have already filled not even halfway my target configuration. Regarding these 2 disks, my first 2 questions are:
Q1 - The OS disk is almost empty (1 % used), which seems almost a waste. I don't know if this is because Windows is more space hungry than a Linux distro but I was wondering if this free space could be used for anything else. [NOTE: If the empty space is not billed, maybe it doesn't matter but still curious about it]
Q2 - I haven't been able to figure out which performance tier the data disk belongs to.
I need to attach extra space and planning on attaching a 64 GB (P6) disk to begin. The preferred final configuration would be a single data disk (in this example of about 96 GB). I understand that the extra space needs to be formatted and mounted. My questions are:
Q3 - Can I accomplish this objective with fdisk and mkfs or would I need to use any special tool?
Q4 - Because the original data disk and the new one probably belong to different performance tier, how do I control the performance tier of the final disk?
As I mentioned, the final goal is to publish it in the Marketplace:
Q5 - Which special considerations should I keep in mind given the final objective?
Thanks.

Answer 1

@colchon753

I wanted to note that the 32GB of diskspace for data that is typically mounted at /mnt is a temporary disk, so don't store anything here that you want to be persistent.

Q1. The default virtual hard disk size for the operating system (OS) is typically 30 GB on a Linux VM in Azure. The OS disk should be mounted at / and you can store additional data on here.
Q2. The current data disk is likely the temporary disk, which is why you will not see it when selecting Disks from the VM settings. Do not spread data between the temporary disk and Data disk as the temporary disk is not persistent.
Q3. Yes, you can format and add a filesystem with your preferred method. We walk you through one method in our documentation here.
Q4. As stated do not spread data between the temporary disk and data disk. For ease of management I recommend creating separate disks rather than relying on things like LVM or RAID. It is easy to expand disks in Azure without adding the complexity of these systems.
Q5. This page walks you through the steps of preparing a VM for the Marketplace. Please review and let us know if you have any questions.

Hope this helps! Let us know if you have further questions or issues and we will do our best to assist.

-------------------------------

Please don’t forget to "Accept the answer" and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.

Answer 2

Hello @deherman,
Thank you for the info. It clarifies most of it but I have a quick follow-up Q. It's clear that the temporary space is useless for my purposes and I'll simply ignore it. The easiest solution would be to expand the /home/azureuser directory (falling under the / directory of the OS disk). You recommend "creating separate disks" but also mention that "It is easy to expand disks in Azure." I understand the first option but that would require me to mount the new filesystem in a new subdirectory (my interpretation is that both disks would work somewhat independently even if controlled by the same OS). For my stated objective (expanding /home/azureuser), it sounds like the second solution is a better fit. Is this (https://learn.microsoft.com/en-us/azure/virtual-machines/linux/expand-disks) the documentation that I should be following? If so, I still have the doubt of which would be the performance-tier of the expanded directory.
Thanks,
Arturo