Concluding My Summit, Conference & Community Engagements for 2014

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After Redmond (MVP Global Summit 2014), which was a great experience I flew to Berlin to attend and speak at the Microsoft Technical Summit 2014 on “What’s New In Windows Server 2012 R2 Clustering”. Germany has a seriously engaged ITPro & Dev scene, that’s for sure, and the session room was packed! Afterwards some interesting questions popped up in the hallways. That’s great as question really make us think about technologies and solutions from other view points and perspectives.

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After Berlin I was off to Experts Live 2014 in Ede (The Netherlands) where I presented on “The capable & Scalable Cloud OS”. The talk went well and I had a great crowd attending with whom I had some great chats after the session.

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That concluded the third leg of my international road tour where I invest in myself, the community & the people I work with. Never ever stop learning Smile. Normally this also concludes my traveling schedule for 2014 unless I’m needed/requested somewhere to help out. Being an MVP is about sharing in the community. The only way to prosper is to share the knowledge, experience and the wealth. It provides for a healthy ecosystem from which we all reap the benefits. This should be promoted and facilitated. There is too much expertise & knowledge not being leveraged due to the fact it’s economically unfeasible, and that’s a waste when people are screaming for IT skills. In a war for talent, any waste is surely very counter productive?

Workshop Datacenter Modernization -Microsoft Technical Summit 2014 Germany (Berlin)

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While speaking (What’s new in Failover Clustering in Windows Server 2012 R2) and attending the Microsoft Technical Summit 2014 I’m taking the opportunity to see how Microsoft Germany and partners are doing a workshop which is based on the IT Camps they have been delivering over the past year. There is a lot of content to be delivered and both trainers Carsten Rachfahl (Rachfahl IT-Solutions GmbH) and Bernhard Frank (Partner Technology Strategist (Hosting), Microsoft) are doing that magnificently.

One thing I note is that they sure do put in a lot of effort. The one I’m attending requires some server infrastructure, a couple of switches, cabling for over 50 laptops etc. These have been neatly packed into road cases and the 50+ laptops had been placed, cabled and deployed using PXE boot /WDS the night before. Yes even in the era of cloud you need hardware especially if you’re doing an IT Camp on “Datacenter Modernization” (think private & hybrid infrastructure design and deployment).

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Not bypassing this aspect of private cloud building adds value to the workshop and is made possible with the help of Wortmann AG. Yes the attendees get to deploy storage spaces, Scale Out File Server, networking etc. They don’t abstract any of the underlying technologies away, I like that a lot, it adds value and realism.

I’m happy to see that they leverage the real world experience of experts (fellow Hyper-V MVP Carsten Rachfahl) who helps hosting companies and enterprises deploy these technologies. Storage, Scale Out File Server, Hyper-V clusters, System Center and self service (Azure Pack) are the technologies used to achieve the goals of the workshop.

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The smart use of PowerShell (workflows, PDT) allows to automate the process and frees up time to discuss and explain the technologies and design decisions. They take great care to explain the steps and tools used so the attendees can use these later in their own environments. Talking about their own experiences and mistakes helps the attendees avoid common mishaps and move along faster.

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The fact that they have added workshops like this to the summit adds value. I think it’s a great idea that they are held on the last day as this means that attendees can put the information they gathered from 2 days of sessions into practice. This helps understanding the technologies better.

There is very little criticism to be given on the content and the way they deliver it. I have to say that it’s all very well done. Perhaps they make private cloud look a bit too easy Winking smile. Bernard, Carsten, well done guys, I’m impressed. If you’re based in Germany and you or your team members need to get up to speed on how these technologies can be leveraged to modernize your data center I can highly recommend these guys and their workshops/IT Camps.

Hyper-V Guest Protected Network Testing Tip

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I’ve been pinged a few times over the years with people saying that the new protected network feature does not work for them. This setting is set per vNIC of the virtual machine.

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The issue lies in how & what people test, bar any number of other reasons why a live migration might not start or complete.  What people tend to do is disable a NIC to which the vSwitch is connected. But a Protected Network is about media sense loss detection of network disconnects and this requires the NIC to be actually there and enabled. Remember, we’re talking about the NIC on the host connected to the virtual switch. A physical link failure here, meaning that the virtual switch the protected virtual network adapter no longer has network connectivity, will lead to all the VMs with  the protected network enabled do be live migrated to another node in the cluster that still has a connected virtual switch for the same network.  The latter is to avoid  senseless virtual machine migrations to other nodes that might also have lost connectivity due to a failed physical switch.

So the point is that testing by disabling the NIC in the OS will not do. You need to unplug the cables to the virtual switch or disable the port on the switch or even shutdown the switch (a bit drastic).

Do note that it can take a little time for the live migration to kick in,  it varies a bit, but it beats having to wait for the issue to be resolved. You’ll see event id 1255 logged when the VMs lose network connectivity:image

In this day and age with NIC teaming to redundant switches & the fact that you might be using converged networking these tests aren’t as simple as you might think. Also don’t pull out all if the cables used for clustering if you want the cluster to be able to help you out here with a live migration. Because when the other cluster nodes can’t talk to the node your testing in any way it will be kicked out of the cluster, the VMs will go down, be moved to another node and started. This might seem obvious but if you a are using a teamed 10Gbps solution in a converged setup this might cause exactly that.

Another thing to note is that if you have a virtual switch with a dedicated backup network exposed to hosts & VMs that can tolerate down time you might want to disable protected networks on that vNIC as you don’t want to live migrate the VMs of when that network has an issue. It all depends on your needs & tastes.

Last but not least please behave, and don’t do anything silly in production when testing this. Be careful in your testing.

Golden Nuggets: Windows Server 2012 R2 Failover Cluster CSV Placement Policy

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Some enhancements only become truly evident to people when they see them in action. For many features this means something need to go wrong before they kick in. Others are more visible during normal operations. This is the case with the CSV enhancements in Windows Server 2012 R2 Failover Clustering.

One golden nugget here is the CSV placement policy (which really shines in combination with SOFS/Storage Spaces). This will spread ownership of the CSV amongst the cluster nodes to ensure a balanced distribution. In a failover cluster, one node is the “coordinator node” (owner) for a CSV. The coordinator node owns the physical disk resource that is associated with a logical unit (LUN). All I/O operations for the File System on that LUN are are through the coordinator node. In previous versions there is no automatic rebalancing of coordinator node assignment. This means that all LUNs could potentially be owned by the same node. In storage spaces & SOFS scenarios becomes even more important.

The benefits

  • It helps all nodes carry their share of the workload as it load balances the disk I/O.
  • Failovers of CSV owners are potentially quicker and more predictable/consistent as an even distribution ensures that no one node owns a disproportionate number of CSVs.
  • When losing storage access the number of CSVs that are in redirected mode is potentially less as they are evenly distributed. In an unbalanced cluster it could be for all of them in a worse case scenario.
  • When using SOFS with Storage Spaces it makes sure the Storage Spaces Ownership is distributed fairly.

When does it happen

  • Each time a node leaves or joins the cluster. This means you don’t need to intervene manually or via PowerShell to get an even distribution. This goes for both exiting nodes as when adding a new node. The new node will get a CSV assigned if there is any on surplus on one of the existing nodes.
  • The process also works when you start a failover cluster when it has shut down.

When customers see this in action (it’s most obvious when then add a node as then they are normally watching) they generally smile as the cluster does it job getting  the best possible results out of their hardware.