Production VM not accessible to business. Urgent assistance needed

Question

We get a black screen after login and rebooting of VM did not work.

Answer 1

Hello @Alain Wille ,

Thanks for your time on call. I have observed that the IOPS on the temporary disk is exceeding the supported limits for the current VM size. could you please confirm if there are any specific operations or workloads currently running on the temp disk?

To proceed with troubleshooting and identify the root cause (RCA), I recommend upgrading the VM to the P20 and monitoring performance for a period of time. Based on the observations, we can reassess and take further action if required.

The OS disk performance appears to be within normal limits; however, the increased utilization of the temp disk is likely impacting the overall VM performance.

Furthermore, Microsoft does not recommend using B-series VMs for production workloads. I recommend upgrading the VM to a higher tier to achieve more consistent and reliable performance.

Azure B‑series VMs are explicitly designed for workloads that don’t need constant full CPU and benefit from burst capacity. For reference- B family VM size series - Azure Virtual Machines | Azure Docs

Unlike standard Azure VM types that provide fixed CPU performance, B-series VMs operate on a CPU credit model. These VMs accumulate CPU credits when operating below a defined baseline and consume credits when bursting above that baseline. Once the credits are exhausted, the VM is throttled back to its base performance level until sufficient credits are regained. This behavior can lead to performance variability under sustained workloads.

For the better performance upgrade to another virtual machine size- Virtual machine sizes overview

Answer 2

Alain hi,

if u are getting a black screen after login and a reboot did not fix it, this is usually either a windows shell issue or a stuck update, not the VM being down.

At Azure Portal if the VM status shows Running and passes health checks. Then try connecting using serial console from the portal, this often works even when rdp shows a black screen. If it is windows, the most common cause is explorer.exe not starting so once connected via serial console or safe mode check if the user shell is loading correctly. Look if recent Windows Updates were installed before the issue started because failed updates often cause black screen after login.

If possible, use run from Azure Portal to run :) sfc /scannow or review event logs remotely. If nothing works u can try redeploying the VM from the Azure portal which moves it to a new host but keeps disks.

And of coz if this is business critical and production is down open a ticket at msft immediately while troubleshooting, because actually they can check host level issues if needed...

rgds,

Alex