Howto Copy NDMP data written to NAS attached drives?

Last post 01-31-2020, 7:48 AM by johanningk. 2 replies.
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  • Howto Copy NDMP data written to NAS attached drives?
    Posted: 01-30-2020, 3:37 AM

    Hi guys,

    currently running on V11SP16HPK24.

    NDMP Backups have been created to NAS attached Tape Media.
    Restores of this data can be achieved also using NON NAS attached drive pools.

    AuxCopy of this data seems to require a NAS attached drive pool for reading !
    Even worse, if the reading MediaAgent has direct access to drives within the same library enabled, the AuxCopy job tends to load media into the NON NAS attached drives and fails the AuxCopy !

    Is this a bug or a feature ?
    Is there a way to overcome this, other than disabling all NON NAS attached drive pools on the reading MA ?

    Why is it not possible to copy the data using NON NAS attached drives like in case of restores ?

    another thing with this type of AuxCopy, if scalable ressource allocation is NOT used/checked, the AuxCopy process doesn't seem to release drive reservations, in case of a media change. Once all availbale drives have been used once by the AuxCopy, the process goes to "waiting" "not enough drives...."

    any hints ?
    Is this behavior fixed in one of the later releases or HPKs ? (SP16 is the LTS Release)


  • Re: Howto Copy NDMP data written to NAS attached drives?
    Posted: 01-31-2020, 7:22 AM

    Hi Klaus

    It sounds like you have two-way NDMP configured where the NDMP Backup is written directly from the Filer to the Tape Library

    With this type of configuration Commvault is not directly involved in the write process, Commvault is only invovled if 3-way NDMP is configured where the writes will be handled by the MediaAgent. With the two-way NDMP setup, the Source Filer is required to read the data from Tape (as the original writes are coming from the Filer itself). 

    Further to the above, can you please confirm in the Data Path of the Storage Policy Copy, whether there are Non-NAS attached drive pool configured, as this could be why it is selecting the Non-NAS attached drive for usage?

    In regards to reservation, there is an option at the Storage Policy level "Caching Resource Reservations", can you please check whether this is enabled?



  • Re: Howto Copy NDMP data written to NAS attached drives?
    Posted: 01-31-2020, 7:48 AM

    Hi Winston,

    you're right regarding the backup itself.
    The data is written die NAS attached drives during the backup.
    PrimaryCopy only has NDMP attached drives configured as data paths.

    But when reading data, my expierience is, that ANY drive capable of mounting the required media connected/configured w/ the MediaAgent used as Source MediaAgent/for reading, is considered valid.
    Data paths listed in the SPC are not prioritized over other available drive paths configured to the same library on that MediaAgent.

    If you move the tape media to a different library it is not required to adjust data paths in the SP/SPC to read the data from that tape media. Only if writing is intended, valid data paths have to be defined in the SPC.

    For restores you are able to restrict read operation to a specific drive pool, for auxcopies can only be restricted to a MediaAgent.

    The destination drive pool has data paths to a different library only. Therefore this does not interfere.
    These drives are not NAS attached anyways.

    The MediaAgent used for AuxCopy has the controlling function for the NAS attached drives as well as locally attached drives within the same libary. (I now disabled the local attached drivepool to avoid mounting of media to those drives)

    Restore of NDMP data, originally written to NAS attached drives, is absolutely no problem if your MediaAgent only has direct attached drives connected.
    Media is mounted to an available drive (e.g. Windows : \\.\Tape0) and restores are processed.

    The AuxCopy on the other hand requires NAS attached drives to read the data. (and I don't understand why)

    The Resource Reservation Cache option is NOT checked in the StoragePolicy settings.


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