Sun StorageTek Virtual Tape Control Software (VTCS)
 
Sun StorageTek 9840C Tape Drive
 
Sun StorageTek Enterprise Library Software (ELS)
 
Sun StorageTek VSM5 System
 

PLA-Support>Sun Systems>TAPE>Library Software>SN-TP: MAINSW VTCS
 

Applies to:

Goal

How to recover VTVs from an MVC that has a data check.
How to recover data from an MVC with a datacheck.

Solution

To recover VTVs from an MVC that has a data check, there are two options:

Option A - If all VTVs on the MVC are also linked to other MVCs, then:

   1. Run MVCDRain with the EJect option.  

This recovers all VTVs and removes the MVC from service.  The MVC will have a status of 'J' which indicates it is Logically Ejected.

   2. Run MVCRPT DET for the MVC to verify it contains a zero VTV count.

   3. Physically eject the MVC from the ACS using the HSC EJect command
 
   4. Enter into the ACS a new volume with the same external and internal volser as the one that was ejected.

   5. Run MVCDRAIN without EJect to make the MVC available.  The MVC will have a status of Not Initialized until it is used again by VTCS.

Note that if the VTCS CONFIG GLOBAL parameter RECALWER is set to NO, then if a VTV has a read data check, VTCS will attempt to recall the VTV from the alternate MVC if available since the alternate copy of the VTV may not have a read data check.  Using RECALWER=YES (the default) will allow VTCS to recall the VTV that has a read data check.

Option B - If all VTVs on the MVC are only linked to the one MVC and have no other MVC copy, then:

   1. Run VTCS AUDIT for the MVC.  The audit will probably fail.

The audit attempts to read the VTV metadata sequentially from the MVC.  The audit fails when it encounters the data check, which leaves the MVC in an auditing state.  This  prevents VTCS from selecting the MVC for output.

   2. After the audit, run an MVCDRAIN without the EJect option. 

This recalls the VTVs before the data-check area in ascending block-id order and the VTVs after the data-check area in a descending block-id order.  Processing the VTVs in this sequence ensures that VTCS recovers as many VTVs as possible from the media.      

    3. Run MVCRPT DET for the MVC to verify it contains a zero VTV count. 

Any VTV that could not be retrieved by MVCDRAIN and does not have a copy on another MVC will need other methods to recover or recreate the data.

    4. Physically eject the MVC from the ACS using the HSC EJect command

    5. Enter into the ACS a new volume with the same external and internal volser as the one that was ejected.

        a. If the bad MVC was removed with no VTVs remaining linked then run MVCDRAIN EJect followed by MVCDRAIN.

        b. If the bad MVC was removed with VTVs that could not be drained from the MVC, run the VTCS utility AUDIT MVC.

         This will update the CDS to reflect the fact that there are no VTVs linked to the MVC. 
         If the MVC still has the Data check status, then run MVCDRAIN EJect followed by  MVCDRAIN.

     6. Issue D MVC(volser) to verify the status is now correct.  MVC will most likely have a status of Not Initialized.

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