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TheVMinator
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vROPs Disk vs. Virtual Disk vs. Datastore Metrics

What is the difference between these three types of metrics for a virtual machine?

1. Disk

2.  Virtual Disk

3.  Datastore

http://pubs.vmware.com/vrealizeoperationsmanager-64/topic/com.vmware.ICbase/PDF/vrealize-operations-...

I want to see the average total latency for a single virtual machine including all of its virtual disks, should I use the "datastore" metric or should I use the "disk" or "virtual disk" metrics and sum them? 

If I use "datastore" will that include informaiton from other virtual machines that have disks on the same datastore?

thanks!

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carvaled
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So a quick one.. if you want more  detail let me know

The way I typically troubleshoot latency issues is by starting with the VirtualDisk metrics... this gives me a good indication of what the VM is experiencing... once I have looked at the aggregate and determined the VM is suffering I will then break it down to the individual SCSI id's of the disks and determine if it's a problem for only a specific disk on a dedicated datastore etc...

Using datastore latency is not always a good indication as you can have some faulty hosts but because the datastore metric is an aggregate of all ESX hosts latency to the datastore it can actually mask a real performance issues....

For example if you have 10 hosts connected to a datastore and 9 have low latency but 1 has high latency the latency is averaged out for that datastore to look like the performance is fine when in reality 1 host is suffering along with its VM's...

When I find high latency on a VM and then look at the datastore latency and it's low I suspect a problem with the paths to the storage for that host...so I will then look at the HBA latency for the host to break it down to a path.

Hope that helps.

Cheers

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carvaled
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So a quick one.. if you want more  detail let me know

The way I typically troubleshoot latency issues is by starting with the VirtualDisk metrics... this gives me a good indication of what the VM is experiencing... once I have looked at the aggregate and determined the VM is suffering I will then break it down to the individual SCSI id's of the disks and determine if it's a problem for only a specific disk on a dedicated datastore etc...

Using datastore latency is not always a good indication as you can have some faulty hosts but because the datastore metric is an aggregate of all ESX hosts latency to the datastore it can actually mask a real performance issues....

For example if you have 10 hosts connected to a datastore and 9 have low latency but 1 has high latency the latency is averaged out for that datastore to look like the performance is fine when in reality 1 host is suffering along with its VM's...

When I find high latency on a VM and then look at the datastore latency and it's low I suspect a problem with the paths to the storage for that host...so I will then look at the HBA latency for the host to break it down to a path.

Hope that helps.

Cheers

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sxnxr
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If you have not already upgrade to 6.4 as there are some new dashboards that are good and may give you what you need

TheVMinator
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OK great - thanks again!

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