Dear Chrys, I should you call you teacher, since I’ve joined your lessons many times until now and I have to pay my respects to you!

The reason for disabling IPv6 on the Nics of each nodes are based on what each Nic does.

On the heartbeat network where node nics are joined as point to point nic (or nic to nic via a cross cable or simple patch cord if the nics support it-most do nowadays), we have no need for any other traffic. Not only ipv6 but also no client for Microsoft networks nor anything else, since I need simple Ipv4 communication between the nodes.

For the RSO nics -especially- if the RSO is a dedicated storage for the cluster which is well accepted by Microsoft’s guidelines, we still don’t need it. Since its again a point to point connection with the RSO and needs no interference with any other network device or client.

Now as far as Production nics are concerned, I will not argue with your comment. Especially if the domain DC is a 2008 Server or newer. However we have seen many times not correct name resolving, due to DNS issues of course, or other networking issues that are not part of the article’s scope. Most of the times this happens also when IPv6 tends to work prior to IPv4 resolving and issues do come up from times to times. But again this is something that has to do with the rest of the network, not the cluster itself. The whole IPv6 idea looks great but I would personally not put it on a cluster where high availability is the main objective and it should be able to pass resources, even when DCs are down.

On the other hand, IPv6 may be incorporated in almost every Microsoft app, like Windows mail or home group etc, though this is a cluster and clusters have sometimes unexpected behavior or require extreme precautions when maintaining. For example let’s not forget you can’t use Microsoft update on a cluster node unless you go over the cluster windows update process. Or even more let’s not forget some cheap old tricks that were required once setting up clusters over WinNT Enterprise where we applied SP6 and then SP4 in order to make the cluster finally work. To make a long story short and forget the dreadful and stressful past of clusters which I personally don’t want to remember, I will conclude to the following: Setting up a cluster may have become easier but this doesn’t mean that you should do what you usually do on normal servers. They have an attitude of their own and thus I personally prefer to make them as lightweight as possible.

I do promise that I will test IPv6 functionality the next time and update the article accordingly!!!

Once again with all the respect a student should show to the teacher, respectfully yours,

Chrysostomos Psaroudakis
IT Director-Quality Assurance Manager
Creative People
7-9 Anagenniseos St., Building A
GR-14342,
Nea Philadelphia,
Greece
Tel: +302155513812
url: https://creativepeople.gr

http://blogs.technet.com/b/askpfeplat/archive/2013/06/17/ipv6-for-the-windows-administrator-why-you-need-to-care-about-ipv6.aspx

“It is unfortunate that some organizations disable IPv6 on their computers running Windows 7, Windows Vista, Windows Server 2008 R2, or Windows Server 2008, where it is installed and enabled by default. Many disable IPv6-based on the assumption that they are not running any applications or services that use it. Others might disable it because of a misperception that having both IPv4 and IPv6 enabled effectively doubles their DNS and Web traffic. This is not true.
From Microsoft’s perspective, IPv6 is a mandatory part of the Windows operating system and it is enabled and included in standard Windows service and application testing during the operating system development process. Because Windows was designed specifically with IPv6 present, Microsoft does not perform any testing to determine the effects of disabling IPv6. If IPv6 is disabled on Windows 7, Windows Vista, Windows Server 2008 R2, or Windows Server 2008, or later versions, some components will not function. Moreover, applications that you might not think are using IPv6—such as Remote Assistance, HomeGroup, DirectAccess, and Windows Mail—could be.
Therefore, Microsoft recommends that you leave IPv6 enabled, even if you do not have an IPv6-enabled network, either native or tunneled. By leaving IPv6 enabled, you do not disable IPv6-only applications and services (for example, HomeGroup in Windows 7 and DirectAccess in Windows 7 and Windows Server 2008 R2 are IPv6-only) and your hosts can take advantage of IPv6-enhanced connectivity.”

http://blogs.technet.com/b/askpfeplat/archive/2014/09/15/a-5-second-boot-optimization-if-you-ve-disabled-ipv6-on-windows-client-and-server-by-setting-disabledcomponents-to-0xffffffff.aspx