VCP4.0 Four Questions Daily –17 Oct,2009

What is the maximum number of virtual processor supported by virtual machine?

Number of virtual processor supported are 8. However virtual machine cannot have more than CPU that the logic CPU present on the physical hardware or 2 times the logical cpu if HT is enabled.

How is the ESX version compatible with VMI paravirtualisation?

ESX4.0 supports VMI and as well ESX3.5 & VMWare workstation 6.0 & above supports it. But Virtual machine with VMI enabled cannot be vMotion to host which do not support VMI. However you can do cold migration of this VM to no supported esx Host.

What is NPIV and it’s limitation with regards to Virtual Machine?

NPIV stands for N-Port ID Virtualization and it is virtual HBA assigned directly to virtual machine. In other words HBA is also virtualized. In this case Single HBA Port is shared among multiple virtual port. Each NPIV assigned WWN,WWNN (World Wide Node Name) and WWPN (World Wide Port Name). WWN’s are assigned by Virtual center.

Following are the limitation of NPIV

  • Only for RDM.
  • HBA must support it.
  • SAN must support it.
  • each VM can have 4 NPIV port, so each VM can utilize maximum of 4 physical HBA’s

What are various types of nic card supported in esx4.0?

  1. Flexible: run vm’s created on esx3.0 & above. Default adapter for 32-bit OS
  2. e1000: default adapter for 64-bit OS
  3. vmxnet 3: available only on Hardware version7.0 contains enhanced features and performances
  4. Enhanced vmxnet: enhanced performance

How does hardware upgrade of virtual machine affect nic card types?

if the adapter type was vlance, the adapter type on the upgraded virtual machine is flexible.

if the adapter type is vmxnet, the adapter type on the upgraded virtual machine is vmxnet, but you cannot change the type to vlance.

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