Five "Ask SGI" questions were discussed with approximately eight
members of SGI's software development group.

Q:  DMF's filesystem backup script do_xfsdump dates back to the days
    when multi-reel backup tapes were the norm.  Are there any plans
    to update it to meet modern requirements?  Such as:

        - multiple dumps on a single tape, possibly appending
          incremental dumps to the tape containing the one they're
          based on

        - dump filesystems to disk and then copy those files
          efficiently to tape

        - better management of the pool of backup tapes

        - possibly managing the movement of tapes between on-
          and off-site locations

A:  The option of xfsdumping to disk, and then copying the resulting
    disk files to tape has been implemented and will be released as
    part of ISSP 2.6 (May 2012).

    The same release will include an xfsdump option which increases
    considerably the speed of an incremental backup, at the cost of
    a more complicated xfsrestore sequence to reload files from it.

    Work has also gone into parallising the backup of filesystems,
    with significant reductions in the total elapsed time taken.

    Other enhancements may come over time as site requirements become
    clearer, and details of these were requested.

Q:  A large new site commented on the cumbersome nature and interface
    of OpenVault.  They want to know when it will have a user friendly
    interface.

A:  Significant portions of OV are being rewritten, and OV 2.0 is
    likely to be released in October 2012.  This will include
    changes to make configuration more automatic and more robust.
    The ov_shelf command for configuring COPAN MAID, to be released
    sooner than then, is an example of the approach which will be
    adopted more widely.  The manual will be rewritten for OV 2.0.

Q:  Are there any plans for a DMF client facility for Windows users,
    preferably integrated into the Windows Explorer desktop?

A:  An experimental Windows interface based on the recently release
    SOAP interface to DMF has been created, but will not be released
    in its current form due to unresolved security issues.  Monash Uni
    expressed an interest nonetheless, and SGI agreed to make a copy
    available to them.

Q:  When will the Parent Inode Pointer (PIP) feature be included in
    XFS, and will DMF be able to take advantage of it immediately?

A:  The PIP code has been given to the XFS open source community, but
    interest is limited due to concerns about performance impacts.
    When used, it could be invoked millions of times in rapid
    succession, so the performance impact has to be near zero to be
    acceptable.  SGI is unlikely to be able to put extra resources
    into this for at least twelve months.

    Apart from allowing DMF to have policies based on path- or
    file-names, it was noted that the xfsrepair utility would also
    benefit from such a feature.

Q:  When DMF is busy, it was noticed that all the daemon threads
    are running in the same CPU, and the same for dmmigrate.  Is this
    deliberate?  They would run faster if additional idle CPUs could
    be used.

A:  The developers were unaware of this behaviour, and if confirmed
    would consider it to be a bug.  They plan on investigating it.
    The site is asked to file a case with SGI Support.