Azure VM limits should be visible on VM Overview page graphs
In a support case I found one of my VMs was being throttled because it was over disk write limit; the performance (other colors, not red) and limits (in red) should be on the graphs on the overview. This seriously impacts availability when VMs are being throttled and makes for an insidious and hard to understand issue. All performance limits should be visible! Please implement?
These new metrics added in September 2020 can help monitor and alert on iOPS limits.
Here are the new metrics that help diagnose disk IO capping:
Data Disk IOPS Consumed Percentage
Data Disk Bandwidth Consumed Percentage
OS Disk IOPS Consumed Percentage
OS Disk Bandwidth Consumed Percentage
Here are the new metrics that help diagnose VM IO capping:
VM Cached IOPS Consumed Percentage
VM Cached Bandwidth Consumed Percentage
VM Uncached IOPS Consumed Percentage
VM Uncached Bandwidth Consumed Percentage
Steve Kessler commented
Absolutely great idea and very much needed.
Here is a detailed write-up outlining the problem, the impact on VMs which exceed family size limits, how to analyze the limits and compare them to performance metrics and suggested implementation solution.
Mike Wedderburn-Clarke commented
This is a great idea and would help everyone a lot. I have had a few times when we've experienced issues and eventually found out it was VM limits that we couldn't see and didn't get warnings about.
You can tell no one at Microsoft has thought about trying to compare Azure VM performance against their family size limits: size limits for network throughput are listed in aggregated (in & out) Mbps, while they are reported in MBps separately for in and outbound. Here's an example of the spreadsheet I had to build to calculate a comparison: