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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A gathering of links, part 3   Leave a comment

Sorry for the lack of content. I have something I can write about, I think, but work is getting in the way.

For now, a gathering of links instead.

Cripes! I need to do these more often, this took me forever.

If you find these useful, please rate this blog post or leave a comment. There’s really no need for me to spend my morning doing this if no-one’s going to read it. 🙂

Real world scenario issues with VMQ   Leave a comment

Last week Microsoft published part 1 in an article series about VMQ, detailing how VMQ works and trying to clear up some misconceptions about the technology.

It’s well worth the read but the main reason I mention it is because a colleague of mine ran into an issue that’s very much related to VMQ.

The customer is a large hosting provider and they experienced poor network performance when doing backups and live migrations over their 10 Gbit infrastructure. Very important to know though is that they use a virtual switch in Hyper-V to provide vNICs  for backup and LM.

As the Microsofts article states, you won’t get 10 Gbit out of a Hyper-V switch:

Many people have reported that with the creation of a vSwitch they experience a drop in networking traffic drop from line rate on a 10Gbps card to ~3.5Gbps. This is by design. With RSS you have the benefit of using multiple queues for a single host so you can interrupt multiple processors. The downside of VMQ is that the host and every guest on that system is now limited to a single queue and therefore one CPU to do their network processing in the host. On server-grade systems today, about 3.5Gbps is amount of traffic a single core can handle.

Their bandwidth was somewhat lower, around 3 Gbps, but that’s most likely due to having older hardware.

I’m not sure how they’re going to resolve this but my suggestion was to use separate, physical, NICs for backup and, if needed, for LM.

As I don’t have enough information about how they’ve designed their Hyper-V environment I’m not sure if they’ve scaled up or out. If they scale out, bandwidth for LM should be less of an issue as fewer VMs lives on each host but at a certain point you’re still going to need bandwidth (unless you plan on patching your hosts continuously).

The takeaway from this is that when designing high-end environments, it pays to know the nuts and bolts of the technology you’re using.

Posted 20 September, 2013 by martinnr5 in FYI, Technical

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Some unusual behaviour from Best Practice Analyzer   Leave a comment

A customer of mine recently ran a Best Practices Analyzer scan on his new Hyper-V 2012 setup in order to make sure everything was by the book.

Besides a couple of minor issues one warning stood out to him: “The memory configuration for one or more virtual machines might require the use of Smart Paging if the virtual machine is rebooted, and the specified location for the Smart Paging file is the system disk of the server running Hyper-V.”

He was sure there was no way the Smart Paging file wasn’t located on his CSV’s and decided to check. Sure enough, it’s located on a CSV:

Smart Paging file location

The only hit I get when searching for this exact error message is a TechNet Wiki article telling you not to store the Smart Paging file on the system disk. Thanks, I guess. 🙂

We’ve come to the conclusion that this is a bug in the BPA as it complains on all his VMs, despite them all being correctly configured.

Has any one of you reading this encountered this behaviour?

Posted 17 September, 2013 by martinnr5 in FYI, Technical, Tools

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A gathering of links, part 2   Leave a comment

I’m not sure that I should keep using the “part n” moniker when naming these posts but for now that’s the best I got. We’ll see what happens further down the road.

During my vacation and the couple of weeks I’ve been working I’ve collected quite a few interesting links:

  • Steven Ekren describes in detail a new feature in Hyper-V 2012 (that I’ve missed) that Live Migrates a VM if a critical VM network fails.
  • Jose Barreto explains how to manage the new SMB3 features in Windows Server 2012 R2 through PowerShell.
  • Thomas Maurer has a step-by-step post on how to set up the new network virtualization gateway in Hyper-V 2012 R2.
  • Ben Armstrong details how to use Powershell in order to keep your Hyper-V replicas up to date with the source VM.
  • If you’re interested in Dell’s new PowerEdge VRTX cluster in a box, check out this article on the Microsoft Storage team blog.
  • Over at Hyper-V.nu Marc van Eijk has a really interesting article series on how to set up Hyper-V hosts using bare metal deployment in Windows Server 2012 R2 and System Center VMM 2012 R2. So far part 1 and part 2 have been posted.
  • Didier Van Hoye takes a thorough look at RDMA and not only talks the talk, he walks the walk as well. Funny and informative, as always.
  • vNiklas rescues missing VMs after a storage migration job went haywire. Strange enough he didn’t use one line of Powershell though. 🙂
  • Ben Armstrong shows how to import VMs to a new Hyper-V server without encountering issues due to incompatibilities by using some clever Powershell.
  • If you still need more RDMA check out Thomas Maurers post on the subject.
  • If you want to use Powershell in order to copy files to a VM using the new RDP over SMBus functionality in 2012 R2, vNiklas got you covered.
  • Another post from Thomas Maurer, this time he explains the features of the Cisco UCS Manager version 1.0.1 add-in for VMM and how to install it.
  • Finally, a post about CSV cache from Elden Christensen over at the Failover Clustering and Network Load Balancing Team Blog.

Posted 13 September, 2013 by martinnr5 in A gathering of links, Documentation, Elsewhere, FYI, Technical

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DPM storage calculations   Leave a comment

I’m posting this as I couldn’t find a good single point of reference for how to calculate how much storage your DPM implementation might need.

First off; here are the formulas that DPM uses to calculate default storage space if you want to do the math yourself. Sometimes this is the fastest way if you only need a rough estimate for a simple workload. These don’t take data growth into consideration though.

If you need more complex calculations there are a couple of calculators for DPM:

As mentioned above none of these are for DPM 2012 but if all you need is an accurate estimate of how much storage a DPM implementation will use they’ll do just fine.

Something else worth mentioning is that they don’t take into consideration the new limits of Hyper-V in Windows Server 2012 but if you need to protect a cluster larger than 16 nodes you’d probably want to do the math on your own just to be sure anyhow. 🙂

The first calculator is the most detailed but only covers Exchange up to version 2007. I never use this my self.

The DPM Volume Sizing Tool is actually a set of scripts and Excel sheets that you use to gather actual data from your environment if you want to, along with a couple of Word documents on how to get the ball rolling.

The latest version of the stand alone calculators for DPM 2010 are more detailed than the DPM Volume Sizing Tool but the Exchange calculator is not as detailed as the older one for Exchange and DPM 2007. In addition, these only cover a few of the workloads that DPM can protect.

Personally I do the math myself and if I need to use a calculator I manually enter values into the Excel calculator from the DPM Volume Sizing Tool as this calculator both handles all workloads that DPM can protect and also gives me a good summary of the storage needed.

It’d be nice to see Microsoft develop a single Excel calculator for all workloads and DPM 2012 but that doesn’t seem likely so we’ll make do with what we got.

Posted 12 September, 2013 by martinnr5 in Documentation, Elsewhere, Technical, Tools

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Back from my vacation   Leave a comment

Just a short mention that I’m back from a five week vacation which was the reason for the lack of updates here.

This week I’m just trying to get back into the swing of things but I’ll be back with a proper post next week.

Posted 29 August, 2013 by martinnr5 in Meta

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