A First Look at Hyper-Vs Virtual Fibre Channel Feature (Part 2)

If you would like to read the first part in this article series please go to A First Look at Hyper-Vs Virtual Fibre Channel Feature (Part 1).

Introduction

In the first part of this article series, I explained the basics of working with the new Hyper-V virtual Fibre Channel feature in Windows Server 2012. In this article, I want to conclude the discussion by showing you how to actually use virtual Fibre Channel.

Building a Virtual SAN

The process of setting up virtual Fibre Channel starts with building a virtual SAN. The easiest way to accomplish this is to open the Hyper-V Manager, right click on the listing for your Hyper-V server in the console tree, and then choose the Virtual SAN Manager command from the shortcut menu, as shown in Figure A.

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Figure A

Right click on your Hyper-V host server and choose the Virtual SAN Manager command from the shortcut menu. At this point, the Hyper-V Manager will display the Virtual SAN Manager dialog box, shown in Figure B.

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Figure B: The Virtual SAN Manager is used to create a virtual SAN.

As you can see in the figure above, the top left portion of the window lists the virtual Fibre Channel SANs. Right now the dialog box displays a generic virtual SAN called New Fibre Channel SAN. The server that I am using is a lab machine without a Fibre Channel Host Bus Adapter, but if a Host Bus Adapter were installed in the server, you would see it listed among the virtual Fibre Channel SANs.

Hyper-V also gives you the ability to create a new virtual Fibre Channel SAN by choosing the Virtual Fibre Channel SAN option and clicking the Create button.

The other item that appears in the screen capture shown above is the World Wide Names. As you may recall from the previous article, Hyper-V uses multiple world wide names as a way of facilitating live migrations without losing virtual Fibre Channel connectivity in the process. That being the case, you must provide Hyper-V with a range of world wide names that it can use for this purpose.

If you click on the World Wide Names container, Hyper-V will display the interface that is shown in Figure C. As you can see in the figure, this interface allows you to specify the range of World Wide Port Names that can be dynamically assigned to virtual Fibre Channel ports.

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Figure C: The Virtual SAN Manager allows you to define a range of World Wide Port Names that can be dynamically assigned to virtual Fibre Channel ports.

The other setting that you can see in the figure above is the World Wide Node Name address. This address is dynamically assigned to any new Fibre Channel ports that you create. It is worth noting however, that modifying this setting does not have any impact on previously existing Fibre Channel ports. If you want to change the World Wide Node Name for an existing Fibre Channel port, you will have to remove the port, configure the World Wide Node Name using the interface shown in the figure above and then recreate the World Wide Node Name.

Linking a Virtual Machine

Once you have created a virtual SAN, the next step in the process is to link a virtual machine to the virtual SAN. To do so, right click on the virtual machine for which you want to provide Fibre Channel connectivity and select the Settings command from the resulting shortcut menu. Upon doing so, Hyper-V will display the Settings dialog box for the virtual machine. You can see an example of this in Figure D.

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Figure D: A virtual machine’s Settings page lets you modify the virtual machine’s configuration.

Next, select the Add Hardware container, as shown in the figure above, and then select the Fibre Channel Adapter option from the list of available hardware (shown on the right side of the figure). Click the Add button and you will be taken to the Fibre Channel Adapter page, shown in Figure E.

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Figure E: The Fibre Channel Adapter screen is used to configure the virtual Fibre Channel adapter.

As previously mentioned, this Hyper-V server does not have a Fibre Channel host bus adapter installed. That is the reason why the Virtual SAN drop down list shown in the figure above shows a status of Not Connected. If an adapter were present in the server, we would be able to select the host bus adapter’s corresponding virtual SAN from the drop down list, similar to what you can see in Figure F.

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Figure F: Select your virtual SAN from the drop down list.

Once the virtual SAN has been selected, you can optionally configure the port addresses. As previously mentioned, virtual machines maintain two sets of addresses as a way of facilitating live migrations without losing connectivity to Fibre Channel storage. Figure E shows the World Wide Node Names and the World Wide Port Names that are being used. Although these addresses are grayed out in the figure, you can modify them by clicking the Edit Address button. When you have finished defining the addresses, click the Create Address button, shown in Figure G.

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Figure G: When you finish setting the addresses, click the Create Addresses button.

Conclusion

Now that I have shown you how virtual Fibre Channel works and how to configure it, the next obvious question might be that of whether or not you should be using this feature. Personally, I prefer to stick with using VHD and VHDX based virtual hard disks on traditional storage whenever possible. I find this approach to be easier to manage.

Of course some might be quick to point out that Hyper-V has supported the use of SCSI pass through disks for years and that virtual Fibre Channel could be thought of as a new type of pass through disk. While this is certainly true, it is important to consider why pass through disks were used in the first place.

Pass through disks have historically been used for two reasons. One reason was to isolate a virtual machine’s contents to a specific physical disk. The second reason was because using a pass through disk allowed a virtual machine to get around the storage capacity limitations of the VHD hard disk format. In Windows Server 2012 Hyper-V however, capacity becomes much less of an issue because the VHDX virtual hard disk type offers much greater capacity than VHD based virtual hard disks.

Even so, this does not mean that you should never use virtual Fibre Channel. There is simply no denying the fact that sometimes there is simply no getting around using virtual Fibre Channel. This is particularly true if you want to virtualize physical servers that need to maintain connectivity to SAN storage.

If you would like to read the first part in this article series please go to A First Look at Hyper-Vs Virtual Fibre Channel Feature (Part 1).

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