VSS hardware providers for Shadow Copies of Shared Folders ? - Storage

This is a discussion on VSS hardware providers for Shadow Copies of Shared Folders ? - Storage ; Is it possible to use a hardware provider to create the shadow copy sets used for Shared Folders on Server 2003 or 2008 ? I can not find any documentation saying it can not be done, but I don't see ...

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Thread: VSS hardware providers for Shadow Copies of Shared Folders ?

  1. VSS hardware providers for Shadow Copies of Shared Folders ?

    Is it possible to use a hardware provider to create the shadow copy
    sets used for Shared Folders on Server 2003 or 2008 ?
    I can not find any documentation saying it can not be done, but I
    don't see any way to configure which provider will be used.

    It is not mentioned in the FAQ at http://www.microsoft.com/windowsserv...ew/scrfaq.mspx,
    although I imagine many of the performance related concerns would
    inevitably lead to questions about why the
    copy-on-write load shouldn't be moved onto the storage array.

  2. Re: VSS hardware providers for Shadow Copies of Shared Folders ?

    Which hardware provider? Most know nothing about the NTFS internal
    structure of the data and will snap the whole volume.


    "Geoff" wrote in message
    news:38f9e07c-638b-41df-896e-428dc7977465@v23g2000pro.googlegroups.com...
    > Is it possible to use a hardware provider to create the shadow copy
    > sets used for Shared Folders on Server 2003 or 2008 ?
    > I can not find any documentation saying it can not be done, but I
    > don't see any way to configure which provider will be used.
    >
    > It is not mentioned in the FAQ at
    > http://www.microsoft.com/windowsserv...ew/scrfaq.mspx,
    > although I imagine many of the performance related concerns would
    > inevitably lead to questions about why the
    > copy-on-write load shouldn't be moved onto the storage array.




  3. Re: VSS hardware providers for Shadow Copies of Shared Folders ?

    On Apr 29, 3:17 pm, "John Fullbright"
    wrote:
    > Which hardware provider? Most know nothing about the NTFS internal
    > structure of the data and will snap the whole volume.


    The VSS (Volume Shadow Service) is a MS storage framework, allowing
    storage array manufacturers to write a hardware provider,
    letting them use their own implementation for snapshots.
    Shadow copies for shared folders is supported by VSS. Yes a provider
    will snap the entire volume, but with copy-on-write, only blocks that
    change after the snapshot was created consume storage.
    With the system software provider, software on the server is tracking
    changed blocks and storing them. With a hardware provider that is
    offloaded onto the storage array.

    Other applications supported by VSS, such as Exchange Server and most
    backup applications let you pick a hardware provider to offload the
    snapshot work, so why not Shadow Copies for Shared Folders ? Technical
    reasons ? Marketing reasons ?

  4. Re: VSS hardware providers for Shadow Copies of Shared Folders ?

    I don think it is but would love to here from anyone else.

    "Geoff" wrote:

    > On Apr 29, 3:17 pm, "John Fullbright"
    > wrote:
    > > Which hardware provider? Most know nothing about the NTFS internal
    > > structure of the data and will snap the whole volume.

    >
    > The VSS (Volume Shadow Service) is a MS storage framework, allowing
    > storage array manufacturers to write a hardware provider,
    > letting them use their own implementation for snapshots.
    > Shadow copies for shared folders is supported by VSS. Yes a provider
    > will snap the entire volume, but with copy-on-write, only blocks that
    > change after the snapshot was created consume storage.
    > With the system software provider, software on the server is tracking
    > changed blocks and storing them. With a hardware provider that is
    > offloaded onto the storage array.
    >
    > Other applications supported by VSS, such as Exchange Server and most
    > backup applications let you pick a hardware provider to offload the
    > snapshot work, so why not Shadow Copies for Shared Folders ? Technical
    > reasons ? Marketing reasons ?
    >


  5. Re: VSS hardware providers for Shadow Copies of Shared Folders ?

    If all the shares on a volume were in the same backup set so that one volume
    snapshot backed up all the folders at once, I don't really see a technical
    reason why not.

    If different folders on the same volume are on diffenrent shchedules in
    different sets, the the snapshots would quickly become very inefficient (a
    snapshot of a single folder would be the size of all changed blocks on the
    volume). You would also increase the likelyhood of overlapping operations
    which could cause the backups to fail.


    "Mat Young" Young@discussions.microsoft.com> wrote in message
    news:C902DF4C-780F-4C14-B3E9-E31B081AF084@microsoft.com...
    >I don think it is but would love to here from anyone else.
    >
    > "Geoff" wrote:
    >
    >> On Apr 29, 3:17 pm, "John Fullbright"
    >> wrote:
    >> > Which hardware provider? Most know nothing about the NTFS internal
    >> > structure of the data and will snap the whole volume.

    >>
    >> The VSS (Volume Shadow Service) is a MS storage framework, allowing
    >> storage array manufacturers to write a hardware provider,
    >> letting them use their own implementation for snapshots.
    >> Shadow copies for shared folders is supported by VSS. Yes a provider
    >> will snap the entire volume, but with copy-on-write, only blocks that
    >> change after the snapshot was created consume storage.
    >> With the system software provider, software on the server is tracking
    >> changed blocks and storing them. With a hardware provider that is
    >> offloaded onto the storage array.
    >>
    >> Other applications supported by VSS, such as Exchange Server and most
    >> backup applications let you pick a hardware provider to offload the
    >> snapshot work, so why not Shadow Copies for Shared Folders ? Technical
    >> reasons ? Marketing reasons ?
    >>




  6. Re: VSS hardware providers for Shadow Copies of Shared Folders ?

    On May 28, 8:13 pm, "John Fullbright"
    wrote:
    > If all the shares on a volume were in the same backup set so that one volume
    > snapshot backed up all the folders at once, I don't really see a technical
    > reason why not.
    >
    > If different folders on the same volume are on diffenrent shchedules in
    > different sets, the the snapshots would quickly become very inefficient (a
    > snapshot of a single folder would be the size of all changed blocks on the
    > volume). You would also increase the likelyhood of overlapping operations
    > which could cause the backups to fail.


    Do you know if the system software provider knows about folders within
    a volume to avoid this problem ? As far as I can tell, all providers
    work on a per-volume basis, so they'd all run into the same problem.
    The requestors (backup apps) can look into the volumes and, with some
    application knowledge, do the right thing. For example it could
    compare folders between the original and shadow volume, and conclude
    to not include the folder in the incremental backup onto tape.

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