After doing a range of Memory testing and analysis on a group of Vmware Virtual Machines, the subject of the “Unlimited” Memory/CPU tick box was brought up.

When Resource Allocation’s are setup on a VM there is the option of selecting an Unlimited Limit. It seems as though some people misunderstand exactly what that tick box means.

So i will do my best to try and explain exactly “Unlimited” means.

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Have you ever gazed longingly into the eyes of vCenter 4 Performance Charts and thought to yourself “What the hell does that Counter mean??”.

Since the version 4 upgrade, vCenter now has an even larger amount of Performance Counters for you to use at your disposal. But what do they all mean?

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I’ve had numerous emails about this question which can be found in my VCP410 Practice Exam. So I think it’s time to sort this out once and for all.

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A couple of months ago i spoke about the possiblity of using VMotion over a WAN connection. Well yesterday at VMWorld, VMware announced that long distance VMotion was now supported for up to 200 Kilometers.

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What is VMware VMDirectPath I/O?

VMDirectPath allows guest operating systems to directly access an I/O device, bypassing the virtualization layer. This direct path, or passthrough can improve performance for VMware ESX systems that utilize high-speed I/O devices, such as 10 Gigabit Ethernet. A single VM can connect to up to two passthrough devices.

VMDirectPath I/O is experimentally supported for the following Storage and Network I/O devices:

• QLogic QLA25xx 8 Gb Fibre Channel adapters
• Emulex LPe12000 8 Gb Fibre Channel adapters
• LSI 3442e-R and 3801e (1068 chip based) 3 Gb SAS adapters
• Intel 82598 10 Gigabit Ethernet controller
• Broadcom 57710 and 57711 10 Gigabit Ethernet controllers

VMware regularly adds support for new hardware. Check your hardware’s support at the VMware Hardware Compatibility Guide portal.

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Whilst revising for the VCP4 Beta Exam and also replying to a thread on the VMTN Forum, I’ve come across a couple of instances where there is a lack of “using NPIV in VMware ESX 4″ information. The only good post I can find is Jason Boche‘s post; N_Port ID Virtualization (NPIV) and VMware Virtual Infrastructure, but his post is written and tested using ESX3.5. So I have decided to find out as much information as I can and post it here.

Definition: NPIV stands for N_Port (Node Port) ID Virtualization

What does NPIV do? NPIV is a useful Fibre Channel feature which allows a physical HBA (Host BUS Adapter) to have multiple Node Ports. Normally, a physical HBA would have only 1 N_Port ID. The use of NPIV enables you to have multiple unique N_Port ID’s per physical HBA. NPIV can be used by ESX4 to allow more Fibre Channel connections than the maximum physical allowance which is currently 8 HBA’s per Host or 16 HBA Ports per Host.   See the image above for a graphical representation of NPIV.

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