Disk does not have any datasets existing on the volume

Products

• Disk Backup and Restore - MVS
• DISK BACKUP AND RESTORE

Issue/Introduction

We use CA-1 for tape management, which recognizes Disk tapes as EDM. When looked at some of the tapes/keys in DMS some of the tapes report that there are many files on the tape, however when try to display them DMS reports back that there are no files on the tape. Following are screen shots from CA-1 and from DMS:

From CA-1

From DMS

DMS reports that there are 130 datasets on the tape, but there are no files on the tape when trying to display the contents.

Resolution

For each of data sets written, a DSNINDEX record is created.
For each tape created, an ARCHVOLS record is created for the Primary [PRIM] and the COPY (if one is created).

All DSNINDEX records have a field showing the PRIM ARCHVOLS volser.

If Disk has determined that a data set will require more than one tape to hold it, then Disk will write that data set to as many tapes as needed. When writing that data set is completed, the last tape is closed with no other data sets written to it.

For the data set that was written to multiple tapes, a single DSNINDEX record is created. This record will list the first DASD volser where this data set resided. That DSNINDEX record will also list the first ARCHVOLS volser. 
An ARCHVOLS record is created for every tape created in this multi-volume chain. In each of these ARCHVOLS, there is a "Seq No" field that shows the sequence number of that tape and a "Next Chain" field that lists the next volser in the ARCHVOLS chain.

There is no field that "points up" the chain, only the one field that "points down" the chain.
(If COPY tapes are also created, a chain of COPY ARCHVOLS are created just as the PRIM ARCHVOLS are created.)

Additional Information

NOTE: When the ARCHVOLS is closed the statistics fields are updated: Num of DSNs, Block Count, Byte Count. These fields are never updated thereafter.

Please refer the KB article How Does Disk Determine Tape Utilization, which explains more about multi-volume  ARCHVOLS.

A utility will report the ARCHVOLS records and the DSNINDEX records contained on an ARCHVOLS.

This utility is:

//STEP1  EXEC LISTD
//SYSIN  DD *

Example commands are:

LISTV    [list all ARCHVOLS records]
LISTV VOL=nnnnnn   [list a single ARCHVOLS record]
LISTV VOL=(nnnnnn,nnnnnn,PR*, etc.)  [list several ARCHVOLS or those that match the pattern]
LISTD VOL=nnnnnn   [list DSNINDEX records on a tape]
LISTD VOL=PR*,DUPLICATES    [list DSNINDEX records on these tapes including duplicate data set name entries]

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Please refer to the Disk tech guide Guide for FILES Maintenance, Topic: LISTV Flags.

This displays the vital information that Disk has recorded about the ARCHVOLS, such things as:

First Byte:
x'40' - Volume is a copy of another volume
x'04' - Volume is full (next data set did not fit)

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

For a multi-volume ARCHVOLS, run just the LISTV command to get all the ARCHVOLS records together. Then, you can find each of the records in a chain, from one to the next, etc.,

When all the ARCHVOLS records together, all the "chain" fields can be seen.

An error message example...  

LISTD VOL=nnnnnn 
ADSDM484 3543 NO RECORDS SELECTED 

This can be an easy mistake to make by running a LISTD on a COPY ARCHVOLS. This error message is because the DSNINDEX records have only the PRIM ARCHVOLS noted in the records. 

The ARCHVOLS of the COPY volume does not point to the PRIMARY. Also, look for the message, "ARCHVOLS IS A COPY".

If the KEY CHAIN field is blank, this is because this is the last volume in the chain [or the only volume]. 

Run a LISTV on the record to see the FLAG FIELDS to confirm.

Here is an example of a LISTV report of the last volume (#5) in a multi-volume chain...

 

12019.263  SEP 20, 2019                              A R C H I V E   V O L U M E S                                          PAGE    1

 FRIDAY    12.07 PM                                                                                                    CA DISK r12.5

 

 ARCHIV                                WRITTEN              DATA      BLOCK   K/M/G/T ID VOL FLAGS   COPY   TRUE  SEQ  DEVICE   KEY

  KEY   DATA SET NAME                TIME   DATE   EXPDATE  SETS      COUNT    BYTES  RC CNT 1 2 3   KEY    VOL    NO TYP UNIT CHAIN

 ------ ---------------------------- ------------- -------- ------- --------- ------- -- --- ------ ------ ------ --- -------- ------

 key1    hlq.BK                       0137 2019.219 1999.365       1    323127   9.86G 61   5 048B00         vol1   5 3490DYN1