Archive for the ‘cluster’ Tag

A short note about AD detached clusters in Windows Server 2012 R2   Leave a comment


Yesterday Microsoft posted an article about a new way to deploy clusters in Windows Server 2012 R2 called Active Directory Detached Clusters. As the name implies this type of cluster do not rely on your AD in order to operate, instead using DNS for the Computer Name Objects and the Virtual Computer Objects.

This is great news as I’ve had several clusters acting up due to the domain controller not being reachable but there is one important caveat with this mode:

The intra-cluster communication would continue to use Kerberos for authentication, however, the authentication of the CNO would be done using NT LM authentication. Thus, you need to remember that for all Cluster roles that need Kerberos Authentication use of AD-detached cluster is not recommended.

This means that Live Migration isn’t supported for a Hyper-V cluster, only Quick Migration.

More information here.

Posted 25 March, 2014 by martinnr5 in Documentation, Operating system, Technical

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TechEd Europe 2013 – The rest   Leave a comment


Here’s the rest of the stuff I picked up at TechEd Europe that I felt that I couldn’t fit into any of the other posts. This will not be arranged in any particular order so apologies in advance for that. Also, this isn’t a very long post as most of the important stuff is included in my other TechEd posts.

One thing I’m really interested in is using the cloud – which in my case means Azure – to host your test and QA environments. I have one customer in particular that could really benefit from this as they A) have a huge amount of test and QA server in their own (static) data center which equates to a lot of wasted resources and B) haven’t got enough test and QA environments, resulting in the dreaded “test in production” syndrome.

This customer is quite large though and as I mentioned their data center is anything but dynamic so introducing this model is going to be a huge uphill struggle, both from an economic standpoint as well as a political one.

It is very interesting though so I’ll work on a small and simple proposal to test the waters and see what their reaction is.

Speaking of Azure, the new Windows Azure Pack for your private cloud is another interesting subject but I haven’t had the time to read up on it. I just wanted to mention that one idea that Microsoft presented was to use it as a portal for VMM but when I questioned them why this was a better idea than using App Controller or Service Manager I couldn’t really get a straight answer from them.

As I said though, an interesting subject and I’ll try to get back to it later on.

Finally a short note on the new quorum model in Windows Server 2012 R2. The model is very simple now and is just a vote majority where both nodes and the witness disk gets a vote. The dynamic quorum model automatically calculates what gets a vote though so the best practice from Microsoft is to always add a witness disk and then let the quorum decide if the disk should have a vote or not.

The same dynamic also adjusts for failures in nodes or the witness disk so that a cluster can withstand a lot more abuse now. When talking to Ben Armstrong about a customer that might scale up to roughly 30 hosts he mentioned that one subject that Microsoft needs to communicate better is the fact that large clusters aren’t a problem, especially not in 2012 R2.

And that wraps up my TechEd Europe 2013 notes. I probably missed something or talked about something more than once but so be it. If you should have any questions, feel free to ask away in the comments and I’ll do my best to answer them.

Thanks for reading.

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