Cluster Shared Volumes (CSV)

Server 2008 R2 / 2012 came with a new failover Cluster feature called Cluster Shared Volumes (abbrev: CSV). This is a new feature that enables accessing a LUN from multiple a Windows Failover Cluster Nodes at the same time.  In past, this was not possible on Windows Failover Clusters.

Lets take a look on to the details.

Advantages

  • all nodes in a cluster can access the LUN at the same time, no failover needed
  • if a node’s storage connection fails / has issues, the node can send the write/read requests over LAN to another Node to write/read the needed stuff for him (“The cluster will re-route the communication through an intact part of the SAN or network”, Technet [1] )

Disadvantages

  • From Technet: “Be sure to review carefully what your backup application backs up. Also, for management operating-system based backup, ask your backup application vendor about the compatibility of your backup application with Hyper-V and with Cluster Shared Volumes.” [3]
  • a MUST for Hyper-V, but no advantage for Applications that don’t run more than one instance on the same volume at the same time (e.g. SQL failover cluster, one instance, two servers)
  • NOT SUPPORTED for SQL Server clustered Workloads [4]

Manuals

add storage to Clustered Shared Volumes in Windows Server 2012

Sources

[1] Understanding Cluster Shared Volumes in a Failover Cluster
[2] Recommendations for Using Cluster Shared Volumes in a Failover Cluster
[3] Backing Up Cluster Shared Volumes

[4] Use Cluster Shared Volumes in a Windows Server 2012 Failover Cluster

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VMs over WLAN without NAT

In a Hyper-V for Windows 8 Blog post, a guy of Microsoft wrote about “Supporting VM communication through wireless NICs”. In his Blog Post, he describes a solution where Hyper-V uses a MAC address proxy to enable VM communications over Wireless LANs.

I recommend you read this article by yourself, original post here:
http://blogs.msdn.com/b/b8/archive/2011/09/07/bringing-hyper-v-to-windows-8.aspx