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Cluster Shared Volumes (CSV) is a feature of Failover Clustering first introduced in Windows Server 2008 R2 for use with the Hyper-V role. A Cluster Shared Volume is a shared disk containing an NTFS or ReFS (ReFS: Windows Server 2012 R2 or newer) volume that is made accessible for read and write operations by all nodes within a Windows Server Failover Cluster.
This enables a virtual machine (VM) complete mobility throughout the cluster as any node can access the VHD files on the shared volume. Cluster Shared Volumes simplifies storage management by allowing large numbers of VMs to be accessed off a common shared disk. CSV also increases the resiliency of the cluster by having I/O fault detection and recovery over alternate communication paths between the nodes in the cluster.
While CSV is not required for Live Migration of VMs, it reduces the potential disconnection period at the end of the migration since the NTFS file system does not have to be unmounted/mounted as is the case with a traditional cluster disk. This helps ensure seamless live migration since the physical disk resource does not need to be moved between nodes. CSV increases the chance that a live migration will complete within the TCP reconnect window and ensure a seamless operation to clients.
To use CSV, a Hyper-V VM is configured and the associated virtual hard disk(s) are created on or copied to a CSV disk. Multiple VHDs can be placed on a CSV that in turn are associated with multiple VMs which can be running on different nodes in the cluster.
Cluster Shared Volumes operates by orchestrating metadata I/O operations between the nodes in the cluster via the Server Message Block protocol. [1] The node with ownership of the LUN orchestrating metadata updates to the NTFS volume is referred to as the Coordinator Node. [2] Read / Write operations are passed directly to the Serial attached SCSI, iSCSI, Fibre Channel, or Fibre Channel over Ethernet shared storage via block based protocols.
CSV builds a common global namespace across the cluster using NTFS reparse point. Volumes are accessible under the %SystemDrive%\ClusterStorage root directory from any node in the cluster.
The Cluster will automatically prioritize the most favorable network to route I/O operations by selecting the cluster shared network with the lowest cluster network metric value, this can also be manually configured. Public networks (i.e. networks that connect to users) are assigned higher cluster network metric values by default; this favors I/O operations from using the public network which may already be saturated with user requests.
CSV can be enabled in the Failover Cluster Manager MMC snap-in by selecting 'Enable Shared Volumes' from the information pane after creating a cluster. Additionally, CSV can be enabled using PowerShell:
Import-ModuleFailoverClusters(Get-Cluster[-Name<clusterName>]).EnableSharedVolume="Enabled"
Windows Server 2003, codenamed "Whistler Server", is the sixth major version of the Windows NT operating system produced by Microsoft and the first server version to be released under the Windows Server brand name. It is part of the Windows NT family of operating systems and was released to manufacturing on March 28, 2003 and generally available on April 24, 2003. Windows Server 2003 is the successor to the Server editions of Windows 2000 and the predecessor to Windows Server 2008. An updated version, Windows Server 2003 R2, was released to manufacturing on December 6, 2005. Windows Server 2003 is based on Windows XP.
Files-11 is the file system used in the RSX-11 and OpenVMS operating systems from Digital Equipment Corporation. It supports record-oriented I/O, remote network access, and file versioning. The original ODS-1 layer is a flat file system; the ODS-2 version is a hierarchical file system, with support for access control lists,.
In computing, the Global File System 2 (GFS2) is a shared-disk file system for Linux computer clusters. GFS2 allows all members of a cluster to have direct concurrent access to the same shared block storage, in contrast to distributed file systems which distribute data throughout the cluster. GFS2 can also be used as a local file system on a single computer.
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Shadow Copy is a technology included in Microsoft Windows that can create backup copies or snapshots of computer files or volumes, even when they are in use. It is implemented as a Windows service called the Volume Shadow Copy service. A software VSS provider service is also included as part of Windows to be used by Windows applications. Shadow Copy technology requires either the Windows NTFS or ReFS filesystems in order to create and store shadow copies. Shadow Copies can be created on local and external volumes by any Windows component that uses this technology, such as when creating a scheduled Windows Backup or automatic System Restore point.
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The IBM SAN Volume Controller (SVC) is a block storage virtualization appliance that belongs to the IBM System Storage product family. SVC implements an indirection, or "virtualization", layer in a Fibre Channel storage area network (SAN).
The following tables compare general and technical information for a number of file systems.
Microsoft Drive Optimizer is a utility in Microsoft Windows designed to increase data access speed by rearranging files stored on a disk to occupy contiguous storage locations, a technique called defragmentation. Microsoft Drive Optimizer was first officially shipped with Windows XP.
A clustered file system (CFS) is a file system which is shared by being simultaneously mounted on multiple servers. There are several approaches to clustering, most of which do not employ a clustered file system. Clustered file systems can provide features like location-independent addressing and redundancy which improve reliability or reduce the complexity of the other parts of the cluster. Parallel file systems are a type of clustered file system that spread data across multiple storage nodes, usually for redundancy or performance.
Hyper-V is a native hypervisor developed by Microsoft; it can create virtual machines on x86-64 systems running Windows. It is included in Pro and Enterprise editions of Windows NT as an optional feature to be manually enabled. A server computer running Hyper-V can be configured to expose individual virtual machines to one or more networks.
VHD and its successor VHDX are file formats representing a virtual hard disk drive (HDD). They may contain what is found on a physical HDD, such as disk partitions and a file system, which in turn can contain files and folders. They are typically used as the hard disk of a virtual machine, are built into modern versions of Windows, and are the native file format for Microsoft's hypervisor, Hyper-V.
oVirt is a free, open-source virtualization management platform. It was founded by Red Hat as a community project on which Red Hat Virtualization is based. It allows centralized management of virtual machines, compute, storage and networking resources, from an easy-to-use web-based front-end with platform independent access. KVM on x86-64, PowerPC64 and s390x architecture are the only hypervisors supported, but there is an ongoing effort to support ARM architecture in a future releases.
The Digital Storage Systems Interconnect (DSSI) is a computer bus developed by Digital Equipment Corporation for connecting storage devices and clustering VAX systems. It was designed as a smaller and lower-cost replacement for the earlier DEC Computer Interconnect that would be more suitable for use in office environments. DSSI was superseded by Parallel SCSI.
Adaptable Modular Storage 2000 is the brand name of Hitachi Data Systems mid-range storage platforms.
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