Archive for March, 2011

Unable to clone disk *.vmdk when converting a VM with Paravirtual disk with VMware Converter

March 16, 2011 2 comments

Last week i was trying to migrate/convert (V2V) a VM with Paravirtual SCSI Controllers.

As you all know, Hard disks attached to Paravirtual SCSI Controllers is ‘the way to go’ in vSphere:

– Lower CPU utilization

– Better performance

– Virtualization aware

– …

However, when you try to convert a VM with Paravirtual SCSI Controller, VMware Converter 4.3 throws you a nice error and the task fails with Status: FAILED: An error occurred during the conversion:


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Categories: VMware, vSphere

Enable RSS (Receive Side Scaling) on Windows 2008 (R2) Virtual Machines

March 3, 2011 9 comments

A nice feature of the VMXNet3 vNIC in vSphere is Receive Side Scaling.

For detailed info, check out

I’ll try to summarize it here:

Without RSS, all incoming network traffic is handled by CPU 0.  This could cause a bottleneck on high Network IO machines resulting in an overloaded CPU 0 (where CPU 1, 2, 3, … might be idle).  With RSS enabled, incoming network traffic is handled by all available CPUs.

RSS is available inside a VM on vSphere.  But, you’ll need to have the VMXNet3 adapter in your VM.

Let me show you how to enable this on a Windows 2008 R2 VM.

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Categories: Network, vSphere