2 Replies Latest reply on Dec 10, 2018 2:19 PM by dzli

    Incorrect VirtualDisk.NumberWriteAveraged from QueryAvailableMetric

    dzli Lurker

      I've recently been looking over some of the data collected by QueryAvailablePerfMetrics, and I came across some inconsistent data regarding the Disk Write IO metrics, specifically for Virtual Disks - "virtualdisk.numberwriteaveraged.average" 

      I'm seeing values 50-100x what I see in vCenter - I see around 120 max in the performance graph for virtual disks (customized to show number write average) when doing a test of writing from /dev/random to a file, but the API reports 12000+ (not exactly 100x). Interestingly enough, when I do a iostat on the VM and monitor write rate, I don't see it going past 30, which makes me wonder what these numbers mean.

      I'm calling the API (https://pubs.vmware.com/vi3/sdk/ReferenceGuide/vim.PerformanceManager.html#queryAvailableMetric) using entity = a VM MOR, start time = current time - 1hr, end time = 1hr, interval = PerformanceManagerSummary::getRefreshRate (https://www.vmware.com/support/developer/converter-sdk/conv61_apireference/vim.PerformanceManager.ProviderSummary.html#refreshRate)

       

      Am I calling the API wrong? Or just misunderstanding the metrics?