removed. This problem stems from the fact that NTFS is a shared-nothing filesystem
and cannot be accessed by multiple operating system instances concurrently without
the risk of corruption. This problem was solved with the introduction of Cluster
Shared Volumes (CSV) in Windows Server 2008 R2. CSV allowed all nodes in a cluster
to read and write to the same set of LUNs simultaneously by using some clever
techniques, thus removing the need to dismount and mount LUNs between the nodes.
Windows Server 2012 extended the use of CSV to a specific type of file server, namely
the Scale-Out File Server (SoFS) option, which was a new option available in Windows
Server 2012 and is targeted for use only when sharing out application data such as
SQL Server databases and Hyper-V virtual machines. The traditional style of the
general-use file server is still available for nonapplication data, as shown in Figure
4.13. When selecting the option to create an SoFS, you must select a CSV as the
storage when shares are subsequently created within the file server; the storage is
therefore available to all nodes in the cluster. Because the storage for the share is
available to all nodes in the cluster, the file share itself is also hosted by all the nodes
in the cluster, which now means SMB client connections are distributed over all the
nodes instead of just one. In addition, if a node fails, there is now no work involved in
moving the LUNs, offering an even better experience and reducing any interruption in
operations to almost zero, which is critical for the application server workloads to
which this SoFS is targeted.
Figure 4.13 Enabling active-active through the selection of Scale-Out File Server For
Application Data
The use of SoFS offers an additional benefit. Typically, when a general-use file server
is created as part of the configuration, you have to give the new cluster file server a
NetBIOS name and also its own unique IP address, because that IP address has to be
hosted by whichever node in the cluster is currently hosting the file server. With SoFS,
all nodes in the cluster offer the file service, which means no additional IP addresses