Azure Labs Medium VMs slow: Is 20 Year Old Laptop Performance the New Standard?

Philip Wesley 26 Reputation points
2023-01-06T19:59:57.73+00:00

When originally testing this service, it was determined that medium seemed like an appropriate choice performance-wise but that appears to be no longer the case, as they now appear to perform as well, if not worse than a 20 year old laptop.

Yesterday, I benchmarked the time it took to get from clicking start to performing 3 basic MATLAB tasks on both "Medium" and "Large (Nested Virtualization)" and found that Medium took 20 minutes, with MATLAB hung for a significant portion of that time, while "Large (Nested Virtualization)" took only 5 minutes, with most of the time spent booting the VM and everything else being significantly snappier. This poor performance has caused delays to some of our team's projects, and since we cannot change the VM size after creation, our only choice is to remake all our VMs from scratch if we wish to fix the performance.

I suspect that the reason for this is that Azure Labs VMs that aren't "Nested Virtualization" enabled are using shared vCores, and that it is being shared with too many people. My question is: Has there been any changes that would have made non-nested Medium VMs significantly slower? If so, could you please provide us with a way to fix existing VMs so they aren't so slow anymore? We do not mind a cost increase as long as we get good performance.

Azure Lab Services
Azure Lab Services
An Azure service that is used to set up labs for classrooms, trials, development and testing, and other scenarios.
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  1. kobulloc-MSFT 26,321 Reputation points Microsoft Employee
    2023-01-08T06:32:07.02+00:00

    Hello, @Philip Wesley !

    Why am I getting poor VM performance on my Azure Lab Services v1 (Lab Accounts) "Medium" VM?
    Are you using v1 (Lab Accounts) or v2 (Lab Plans) of Azure Lab Services? Poor VM performance could be tied to the hard drive.

    For v1 (Lab Accounts) "Medium", the guaranteed rates can be relatively slow as they use HDD disks (although faster drives may have been used in the past due to availability).

    For v2 (Lab Plans) "Medium" as well as nested virtualization, an SSD is used which would account for the faster speeds.

    The suggestion for better performance would be to move to v2 (Lab Plans) to take advantage of the SSD speed. If you are already using v2 (Lab Plans), then the recommendation is to open a ticket to see why you aren't getting the expected performance.

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