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IT23574: 'BACKUP VM' USING TRANSPORT METHOD NBDSSL INSTEAD OF HOTADD

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APAR status

  • Closed as Vendor Solution.

Error description

  • 'BACKUP VM' using the VMware Transport protocol HOTADD can
    without apparent error or reason switch to the NBDSSL transport
    in the middle of the backup jobs when attaching guest disks to
    the data mover host.
    There is no pattern to this issue. The defined HOTADD transport
    can be used for a while or only be used once when the switch
    happens. It also does not matter if the data mover host is
    using multiple virtual SCSI adapters or not.
    At the completion of the backup, some hot-added guest disks
    will not be automatically detached from the data mover host and
    these will need to be removed manually by the VMware
    administrator.
    The cause is a defect in the VMware Virtual Disk Development
    Kit (VDDK) 6.0.x and 6.5.x
    https://kb.vmware.com/s/article/51852
    There is no known workaround.
    
    IBM Spectrum Protect Versions Affected:
    IBM Spectrum Protect for Virtual Environments - Data Protection
    for VMware version 7.1.2 and higher and 8.1.x on Windows
    
    Customer/L2 Diagnostics
    
    A data mover client VM trace will display the following message
    when affected by this defect :
    
    <timestamp> [PID] [TID] : ..\..\common\vm\vmvddksdk.cpp(1310):
    <timestamp> error -[TID] [Originator@6876 sub=transport] Cannot
    use mode hotadd to access [<datastorename>]
    <vmname>/<vmname>.vmdk: Cannot mount using this method.
    (Mounting VM vm-<id> using transport hotadd failed : Could not
    create disklib link for device
    \\?\scsi#disk&ven_vmware&prod_virtual_disk#5&effe51&0&000200#{53
    f56307-b6bf-11d0-94f2-00a0c91efb8b}. Reason: The specified
    device is not a valid physical disk device.)
    
    The message expresses the fact that the disk hot-added for
    backup doesn't appear in the expected SCSI slot because the
    VDDK module is expecting to see the device node with a name
    like "\\.\PhysicalDriveX" while it detects a disk found by the
    UUID method that will look like "'\\?\scsi#disk...". This
    results in the hot-added disk not being able to be opened for
    reading.
    
    Initial Impact: Medium
    
    Additional Keywords: vmvstortransport tsm4ve tdp4ve backup scsi
    controller adapter mount attach
    

Local fix

  • None.
    The backup speed can be improved by forcing the use of NBD
    transport instead of the default NBDSSL using the client option
    :
    VMVSTORTRANSPORT HOTADD:NBD
    

Problem summary

Problem conclusion

Temporary fix

Comments

  • The issue is in VDDK 6.0 and 6.5. Fixed in 6.5.2 ep1:
    https://vdc-download.vmware.com/vmwb-repository/dcr-public/9630e
    c55-09a1-4173-965d-33d0eaa24c4a/39fc594c-d7fb-4985-bab9-7faaaba6
    5657/vsphere-vddk-652b-release-notes.html
    HotAdd mode cannot work if disk gets HotAdded to wrong slot
    number.
    If the backup proxy HotAdds a virtual disk to the wrong slot
    number, the device node string becomes something unrecognizable
    such as '\\?\scsi#disk* whereas VDDK expects a disk node string
    in the form \\.\PhysicalDriveX where X is a number. This issue
    is fixed in this release.
    

APAR Information

  • APAR number

    IT23574

  • Reported component name

    TSM CLIENT

  • Reported component ID

    5698ISMCL

  • Reported release

    71W

  • Status

    CLOSED ISV

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2017-12-26

  • Closed date

    2018-06-08

  • Last modified date

    2018-06-08

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    TSM FOR VE DP V

  • Fixed component ID

    5725TVEVM

Applicable component levels



Document information

More support for: Tivoli Storage Manager for Virtual Environments
Data Protection for VMware

Software version: 71W

Reference #: IT23574

Modified date: 08 June 2018


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