Troubleshooting performace ESXi cluster

Armitage318 used Ask the Experts™
Hi, I have a cluster ESXi 6.0 with 9 nodes.
I noticed very bad performances on different VMs on my infrastructure.
According to resources utilization on entire cluster, I would exclude RAM / CPU issue.
I suspect there is some issue on storage side (we use PowerEdge MD3200 / 3800) through iSCSI.
I ran esxtop on some hosts, occasionally I noticed very high DAVG / KAVG values.
My question is: what would you do next?
Through esxtop I can find the "affected" lun.. isn't there a more efficient way to identify the VM (or VMs) that are causing performance issues?
Thank you
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Top Expert 2014

If you suspect the storage then look at the storage management GUI, you won't diagnose a SAN problem using an OS or hypervisor diagnostic,
Top Expert 2014
Did you manage to get into MDSM? I can look through the support logs if you upload them, here is how to collect them -


Hi, I just found in storage's event log several error about "command timeout" on a specific disk.
So, I will raise a ticket to Dell support for further analysis.

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