Author Archives: workinghardinit

Live Migration over SMB Direct leaves more CPU cycles for Virtual RSS (vRSS) in Windows Server 2012 R2

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I recently (January 22nd 2014) gave a WebCast presentation for the Dutch Windows Management User Group (@WMUG_NL) in which I made the case for using SMB Direct with Live Migration to save CPU cycles other (VM) workloads. There are several areas where the CPU cycles are better spent but I used vRSS to show case one scenario.

We’re using a 2 node Windows Server 2012 R2 Hyper-V cluster on Dell PowerEdge R720 servers with Mellanox ConnectX-3 (CSV  &  live migration) and Intel X520-DA (Hyper-V switch), all 10Gbps.

This is what a CPU bottleneck looks like that can be solved by using vRSS in Windows Server 2012 R2.image

The host machines are Hyper Threading enabled. The virtual switch is attached to a switch independent NIC team with dynamic mode. In this setup it’s normal that the sending VM is leveraging both members while the receiving VM traffic is coming in over one member of the host team.

No let’s enable vRSS in the VM and see what this does for this picture.image

Pretty impressive isn’t it. DidierTest03 is the sending VM running on host A and DidierTest04 is the receiving VM that has vRSS enabled and is running on Host B. For vRSS you need both hosts and VMs to run Windows Server 2012 or Windows 8.1. You can see the load is spread across 7 vCPUs in the VM. DidierTest04 has 8 vCPUs. I configured vRSS in the VM to be able to use 7 vCPUs and leave vCPU 0, the default one, alone to handle those workloads.

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Given multiple Logical CPUs & vCPUs we can get line speed with 10Gbps inside a virtual machine. This, ladies and gentlemen is a thing of beauty.

Now tell me, if you have business related needs for those CPU cycles why would you not offload the work that needs to be done for live migration to the NIC via SMB direct? This is about getting maximum VM density, performance & ROI form your infrastructure, whilst saving on servers, power and cooling. When you see the smile on your clients or bosses face, just say “you’re welcome” and smile back Open-mouthed smile.

E2EVC 2014 Brussels

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Ladies & gentleman, on May 30-June 1, 2014 the E2EVC 2014 Brussels Virtualization Conference is taking place. This is a non marketing event by experts in virtualization. So these people design, implement and support virtualization solutions for a living.  E2EVC Virtualization Conference is a non-commercial, it does not run a profit for the organizers or speakers. Everybody volunteers. The attendance fee covers the costs of the conference rooms, coffee breaks and such. The value is in the knowledge sharing and the networking.

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This community event strives to bring the best virtualisation experts together to exchange knowledge and to establish new connections. It’s a weekend event (so people can attend without interrupting their work or customer services. Filled with presentations, Master Classes and discussions you can have 3 days to network and learn from your peers.

So the next event will take place in Brussels, Belgium May 30 – June 1, 2014 in Hotel Novotel Brussels Centre Tour Noire. So my Belgian colleagues, this is your change to be al little Dutch as they have a SPECIAL PRICE FOR BELGIAN RESIDENTS – 199 EUR!

If you’re not Belgian you are also very welcome. So do register for E2EVC 2014 Brussels. If you have knowledge to share, please volunteer to speak. This community event has as a goal to share knowledge and stimulates professionals to present on their subject matters.

A big thank you for Alex Juschin & team for his never ending efforts to help organize this conference!

Unable to retrieve all data needed to run the wizard. Error details: “Cannot retrieve information from server “Node A”. Error occurred during enumeration of SMB shares: The WinRM protocol operation failed due to the following error: The WinRM client sent a request to an HTTP server and got a response saying the requested HTTP URL was not available. This is usually returned by a HTTP server that does not support the WS-Management protocol.

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I was recently configuring a Windows Server 2012 File server cluster to provide SMB transparent failover with continuous available file shares for end users. So, we’re not talking about a Scale Out File Server here.

All seemed to go pretty smooth until we hit a problem. when the role is running on Node A and you are using the GUI on Node A this is what you see:

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When you try to add a share you get this

"Unable to retrieve all data needed to run the wizard. Error details: "Cannot retrieve information from server "Node A". Error occurred during enumeration of SMB shares: The WinRM protocol operation failed due to the following error: The WinRM client sent a request to an HTTP server and got a response saying the requested HTTP URL was not available. This is usually returned by a HTTP server that does not support the WS-Management protocol.”

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When you failover the file server role to the other node, things seem to work just fine. So this is where you run the GUI from Node A while the file server role resides on Node B.

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You can add a share, it all works. You notice the exact same behavior on the other node. So as long as the role is running on another node than the one on which you use Failover Cluster Manager you’re fine. Once you’re on the same node you run into this issue. So what’s going on?

So what to do? It’s related to WinRM so let’s investigate that.

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So the WinRM config comes via a GPO. The local GPO for this is not configured. So that’s not the one, it must come from the  domain.The IP addresses listed are the node IP and the two cluster networks. What’s not there is local host 127.0.0.1, the cluster IP address or any of the IPV6 addresses.

I experimented with a lot of settings. First we ended up creating an OU in the OU where the cluster nodes reside on which we blocked inheritance. We than ran gpupdate /target:computer /force on both nodes to make sure WinRM was no longer configure by the domain GPO. As the local GPO was not configured it reverted back to the defaults. The listener show up as listing to all IPv4 and IPv6 addresses. Nice but the GPO was now disabled.

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This is interesting but, things still don’t work. For that we needed to disable/enable WinRM

Configure-SMRemoting -disable
Configure-SMRemoting –enable

or via server manager

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That fixed it, and we it seems a necessity to to. Do note that to disable/enable remote management it should not be configured via a GPO or it throws an error like

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or

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Some more testing

We experimented by adding 127.0.0.0-172.0.0.1 an enabling the GPO again. We then saw the listener did show the local host, cluster & file role IP address but the issue was back. Using * in just IPv 4 did not do the trick either.

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What did the trick was to use * in the filter for IPv 6 and keep our original filters on IPv4. The good news is that having removed the GPO and disabling/enabling WinRM  the cluster IP address & Filer Role IP address are now in the list. That could be good for other use cases.

This is not ideal, but it all works now.

What we settled for

So we ended up with still restricting the GPO settings for IPv4 to subnet ranges and allowing * for IPv6. This made sure that even when we run the Failover Cluster Manager GUI from the node that owns the file server role everything still works.

One workaround is to work from a remote host, not from a cluster member, which is a good practice anyway.

The key takeaway is that when Microsoft says they test with IPv6 enabled they literally mean for everything.

Note

There is a TechNet article on WinRM GPO Settings for SCVMM 2012 RC where they advice to set both IPv4 and  IPv6  to * to avoid issues with SCVMM operations. How to Add Trusted Hyper-V Hosts and Host Clusters in VMM 

However, we found that IPv6 is the key requirement here, * for just IP4 alone did not work.

Reverting the Forest & Domain Functional Levels in Window Server 2008 R2, 2012, 2012 R2

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Since Windows Server 2008 R2 and now with Windows Server 2012(R2)you can roll back the domain and forest functional level under certain conditions. This was not possible before with previous versions of Windows. In these cases you would have to revert to a restore from backup. Yup pretty hefty so raising functional levels has to be done with care.

Now this isn’t a free fire zone there are some conditions as listed in the table below.

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So you cannot have advanced features like the AD recycle bin enabled in some conditions. Enabling this is irreversible, so you cannot revert the Forest Functional Level of your environment to a level that supports the AD recycle bin when it has been enabled. Today that means from Windows Server 2012(R2) to Windows Server 2008 R2.

You also need Enterprise Administrator rights to do so, which I hope you’ll understand. It’s also a Windows PowerShell only feature (Set-ADDomainMode).

I used this information recently during an upgrade of an Windows Server 2008 R2 domain to Windows Server 2012 where they wanted to raise the domain and forest functional level. As they had a Forest Trust between the (now) Windows Server 2012 forest/domain and another Windows Server 2008 R2 forest/domain. They had enabled the Recycle Bin when still at Windows 2008 R2. They wanted to know if they would have issues with the trust and if so whether they could revert the levels in that case.

Well I could put their mind at ease. Look at the table. Yes you can go back to Windows 2008 R2 Forest Functional level as that’s a version that also supports AD Recycle bin so it doesn’t matter that is enabled.  And no, the forest trust capability is not affected by the forest functional level in this case as all you need there is to be at a minimum level of Windows 2003 to be able to do a forest trust. Forest Trust is enabled from and above Windows Server 2003 Forest functional Level. In a Windows Server 2000 Forest functional Level, Forest Trust is disabled. That means you can do them between forests at different functional levels a long as non of them is lower than Windows 2003. In this case it’s Windows 2008 R2 that’s the lowest, so again, not an issue.

How? Very simple:

Set-ADDomain Mode mydomain.com -DomainMode Windows2008R2Domain

Set-ADForestMode mydomain.com -ForestMode Windows2008R2Forest

Take a look at these TechNet Resources Understanding Active Directory Domain Services (AD DS) Functional Levels  and Set-ADDomainMode for more information.