The data copy process can be handled by the file system or by specialized hardware; in the latter case a hardware VSS provider abstracts the functionality to the operating system. Applications can provide specific support for VSS through VSS writers which control how data is set to a consistent state at the beginning of a VSS operation and maintain that consistency throughout the process, among other functions.
Through the integration between the Volume Shadow Copy Service, hardware or software VSS providers, application level writers and backup applications, VSS enables integral backups that are point in time and application level consistent without the backup tool having knowledge about the internals of each application. For example, in a virtualization product such as Virtual Server 2005 R2 SP1 or Hyper-V in Windows Server 2008, a whole backup of an environment including several virtual machines can be created in a single operation, and the backups produced for the different VSS compatible guests in the system are transactionally consistent at the guest application level and point in time consistent among the different VMs, without the need for the guests to have backup agents installed. Windows software and services that support VSS include Windows Backup, Hyper-V, Virtual Server, Active Directory, SQL Server, Exchange Server, and SharePoint.
Enter the Everpure FlashArray VSS Hardware Provider
The Everpure VSS extension allows users to take volume snapshots while applications continue writing to the FlashArrays.Once taken, the snapshots are saved to the Everpure FlashArray. Note: The VSS hardware provider provides a REST API between the third party backup application and the Purity array. For more information about the REST API, refer to the Everpure REST API Guide. To use the VSS extension, you must install the Everpure VSS hardware provider on the Windows host machine (also known as initiator).
More details on our VSS provider can be found internally here.