VM Disk Read/Write Bytes High, VM Slow

Question

Dear Team

I am writing to bring to your attention some performance issues we have encountered with our recently created VM configuration, Standard B12ms (12 vCPUs, 48 GiB memory).

Last week, we deployed this new VM, and initially, it appeared to be functioning correctly. However, during our monitoring session this morning, we observed a significant increase in disk utilisation after the first 1-2 hours of operation. This increase is notably higher compared to our previous VM configurations, despite the new VM experiencing a lower load.

Additionally, we have noticed that remote sessions to this VM are taking longer to reflect the screen, and at times, the screen goes black. This is a stark contrast to the performance of our previously created VMs, which have been operating without any issues. We have verified that there are no network connectivity problems.

Given these observations, we are seeking your valuable suggestions on how to address these performance discrepancies. Your expertise and guidance in resolving this matter would be greatly appreciated.

Thank you for your attention to this issue. We look forward to your prompt response.

Answer 1

Hi Dalbir Singh,
Thank you for reaching out to us on the Microsoft Q&A forum.

The Standard B-series virtual machines are designed for burstable workloads. If your application requires consistent performance, consider switching to D-series or E-series Virtual machines.

Each disk type has specific IOPS and throughput limits. Consider scaling up your disk or optimizing your workload to manage I/O effectively.

Verify that the disk type (Standard HDD, Standard SSD, or Premium SSD) is suitable for your workload. Premium SSDs typically offer better performance for I/O-intensive applications.

Check if there are any background processes or applications on the Virtual machine that might be causing high disk I/O usage.

Make sure the virtual machine has sufficient CPU and RAM. If it is under-provisioned, it may lead to performance issues, such as slow remote sessions.

Please find the below documents for more information:
Virtual machine and disk performance
Disk performance metrics

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