Tag Archives: Hyper-V

ShadowProtect filter driver causing CSV to run in redirected mode on Server 2012

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Had an issue on some new Server 2012 Hyper-V clustered hosts. Started seeing the following error in the logs:

Cluster Shared Volume 'SERVERNAME' ('') has identified one or more active filter drivers on this device stack that could interfere with CSV operations. I/O access will be redirected to the storage device over the network through another Cluster node. This may result in degraded performance. Please contact the filter driver vendor to verify interoperability with Cluster Shared Volumes. 

Active filter drivers found:
???????????????????????

Yes, those are random characters in the error message, so it’s difficult to track down the filter driver in question.

This seems to match the same issue in Server 2008 R2 – Redirected mode is enabled unexpectedly in a Cluster Shared Volume when you are running a third-party application in a Windows Server 2008 R2-based cluster

In the Microsoft KB notes, they state one of the conditions as being:

  • The third-party application has a mini-filter driver that uses an altitude value to determine the load order of the mini-filter driver.
  • The altitude value contains a decimal point.

Running fltmc.exe on these hosts shows the following filter drivers loaded:

image

The filter driver with the decimal point is stcvsm, the “StorageCraft Volume Snapshot Driver” The problem has only been occurring recently, after I installed ShadowProtect.

I’ve had to uninstall ShadowProtect from these servers until it’s officially supported on Server 2012. According to StorageCraft, that should be 90 days after the official launch date of Server 2012. That means there should be a new version of ShadowProtect around the 3rd of December 2012.

Gotcha: HP Teaming and Hyper-V

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A point to be aware of when setting up a new Hyper-V host on a HP server that’s going to have the Network Configuration Utility (NCU) installed; You must install the Hyper-V role before installing the NCU.

This is as per HP’s recommendation here:
Using HP ProLiant Network Teaming Software with Microsoft® Windows® Server 2008 Hyper-V or with Microsoft® Windows® Server 2008 R2 Hyper-V

The reason for this, according to HP:

If you install the teaming software before installing HyperV, the network adapters may stop passing traffic.

If you’ve already installed both, but in the wrong order, you’ll need to uninstall both the Hyper-V role as well as the NCU.

To uninstall the NCU (I always forget how to do this, and have to look it up), do the following:

  1. Start, Run, ncpa.cpl
  2. Go into the properties of one of the NICs
    2011-08-11 16-28-55_mRemoteNG - FH mRemote Connection List.xml
  3. Select “HP Network Configuration Utility”, and click Uninstall
    2011-08-11 16-29-54_mRemoteNG - FH mRemote Connection List.xml

NLB on a Hyper-V host

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Just a quick gotcha I came up against when I was trying to set up a CAS array on my Exchange 2010 boxes. I kept getting errors when trying to set up a unicast NLB cluster, and the nodes wouldn’t converge.

I ended up figuring out that I had to enable MAC address spoofing on the virtual NICs. The cluster needs to assign the same MAC to both cluster NICs, and this isn’t possible without having that checkbox ticked. This feature is only available in Hyper-V since Server 2008 R2 was released.

I was going to write a more detailed article about it, but as usual, Paul Cunningham’s great blog has it covered already in detail with screenshots.

Some good Hyper-V and Failover Cluster tips on TechNet

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I’ve been browsing the Hyper-V related articles on TechNet while planning to move over to a failover cluster, and have found some useful tips. The TechNet articles are a literal goldmine of information if you can be bothered reading through it all.

They answer some of the initial questions I had when first implementing Hyper-V

If you change the configuration of a virtual machine, we recommend that you use the Failover Cluster Manager snap-in to access the virtual machine settings. When you do this, the cluster is updated automatically with the configuration changes. However, if you make changes to the virtual machine settings from the Hyper-V Manager snap-in, you must update the cluster manually after you make the changes. If the configuration is not refreshed after networking or storage changes are made, a subsequent failover may not succeed or may succeed but result in the virtual machine being configured incorrectly. original here…

For iSCSI: If you are using iSCSI, each clustered server must have one or more network adapters or host bus adapters that are dedicated to the cluster storage. The network that you use for iSCSI cannot be used for network communication. In all clustered servers, the network adapters that you use to connect to the iSCSI storage target should be identical, and we recommend that you use Gigabit Ethernet or a faster network adapter. original here…

You cannot use teamed network adapters, because they are not supported with iSCSI. original here…

On a failover cluster that uses Cluster Shared Volumes, multiple clustered virtual machines that are distributed across multiple cluster nodes can all access their Virtual Hard Disk (VHD) files at the same time, even if the VHD files are on a single disk (LUN) in the storage. original here…

Software requirements for using Hyper-V and Failover Clustering: All the servers should have the same software updates (patches) and service packs. original here…