Managing Bitmaps With DCL Commands

The SHOW DEVICE, SHOW CLUSTER, and DELETE commands have been extended for managing bitmaps.

Determining Bitmap Support and Activity

You can find out whether a bitmap exists for a shadow set by using the DCL command SHOW DEVICE/FULL device-name. If a shadow set supports bitmaps, device supports bitmaps is displayed along with either bitmaps active or no bitmaps active. If the device does not support bitmaps, no message pertaining to bitmaps is displayed.

The following command example shows that no bitmap is active:

$ SHOW DEVICE/FULL DSA0

Disk DSA0:, device type RAM Disk, is online, mounted, file-oriented device,
    shareable, available to cluster, error logging is enabled, device supports
    bitmaps (no bitmaps active).

    Error count                    0    Operations completed                 47
    Owner process                 ““    Owner UIC                      [SYSTEM]
    Owner process ID        00000000    Dev Prot            S:RWPL,O:RWPL,G:R,W
    Reference count                2    Default buffer size                 512
    Total blocks                1000    Sectors per track                    64
    Total cylinders                1    Tracks per cylinder                  32
    Volume label              “TST0”    Relative volume number                0
    Cluster size                   1    Transaction count                     1
    Free blocks                  969    Maximum files allowed               250
    Extend quantity                5    Mount count                           1
    Mount status              System    Cache name      “_$252$DUA721:XQPCACHE”    
    Extent cache size             64    Maximum blocks in extent cache       96
    File ID cache size            64    Blocks currently in extent cache      0
    Quota cache size               0    Maximum buffers in FCP cache        404
    Volume owner UIC        [SYSTEM]    Vol Prot    S:RWCD,O:RWCD,G:RWCD,W:RWCD

  Volume Status:  ODS-2, subject to mount verification, file high-water marking, write-through
     XQP caching enabled, write-through XFC caching enabled.

Disk $252$MDA0:, device type RAM Disk, is online, member of shadow set DSA0:.

    Error count                    0    Shadow member operation count       128
    Allocation class             252
                                             

Disk $252$MDA1:, device type RAM Disk, is online, member of shadow set DSA0:.

    Error count                    0    Shadow member operation count       157
    Allocation class             25

Displaying Bitmap IDs

You can find out the ID of each bitmap on a node with the DCL command SHOW DEVICE/BITMAP device-name. The /BITMAP qualifier cannot be combined with other SHOW DEVICE qualifiers except /FULL. The SHOW DEVICE/BITMAP display can be brief or full; brief is the default.

If no bitmap is active, no bitmap ID is displayed. The phrase no bitmaps active is displayed.

The following example shows a SHOW DEVICE/BITMAP display:

$ SHOW DEVICE/BITMAP DSA1 
Device         BitMap        Size        Percent of 
Name           ID            (Bytes)     Full Copy 
DSA1:          00010001      652         11%

The following example shows a SHOW DEVICE/BITMAP/FULL display:

$ SHOW DEVICE DSA12/BITMAP/FULL 
Device  Bitmap  Size   Percent of Active  Creation    Master  Cluster Local Delete  Bitmap  
Name    ID     (bytes) Full Copy          Date/Time   Node    Size    Set   Pending Name 
                       
DSA12: 00010001  652    11%       Yes  5-MAY-2000 13:30...300F2    127      2%    No   SHAD$TEST




	NOTE: The bitmap name, which is only displayed when you specify SHOW/DEVICE/FULL, takes the form of SHAD$volume-name, followed by many (about 30) unreadable characters. These unreadable characters are used internally to represent the generation number of the bitmap, the time it was created, and other details. The bitmap name is only used internally. The bitmap ID is used by system managers.

Displaying Bitmap Status of Cluster Members

You can specify bitmap information in the SHOW CLUSTER display by issuing the ADD BITMAPS command, as shown in the following example:

$ SHOW CLUSTER/CONTINUOUS

Command > ADD BITMAPS
Command > ADD CSID

View of Cluster from system ID 57348  node: WPCM1          14-FEB-2000 13:38:53

      SYSTEMS              MEMBERS       
  NODE   SOFTWARE    CSID   STATUS    BITMAPS  

 CSGF1   VMS X6TF    300F2  MEMBER    MINICOPY  

 HSD30Y  HSD YA01    300E6                  

 HS1CP2  HSD V31D    300F4                  

 CSGF2   VMS X6TF     300D0   MEMBER    MINICOPY

In this example, MINICOPY means that nodes CSGF1 and CSGF2 are capable of supporting minicopy operations. If a cluster node does not support minicopy, the term UNSUPPORTED replaces MINICOPY in the display, and the minicopy function is disabled in the cluster.

Deleting Bitmaps

After a minicopy operation is completed, the corresponding bitmap is automatically deleted.

There may be times when you would like to delete one or more bitmaps. Reasons for deleting bitmaps include the following:

To recover the memory consumed by a bitmap
To stop the recording of the bitmap

You can delete bitmaps with the DCL command DELETE with the /BITMAP qualifer. You use the bitmap qualifer to specify the ID of the bitmap you want to delete. For example:

$ DELETE/BITMAP/LOG 00010001

%DELETE-I-DELETED, 00010001 deleted