DB2 Version 9.7 for Linux, UNIX, and Windows

db2ckbkp - Check backup command

This utility can be used to test the integrity of a backup image and to determine whether or not the image can be restored. It can also be used to display the metadata stored in the backup header.


Anyone can access the utility, but users must have read permissions on image backups in order to execute this utility against them.

Required connection


Command syntax

Read syntax diagramSkip visual syntax diagram
             | .-,---------------------------. |   
             | V                             | |   
             |   +- -a---------------------+   |   
             |   +- -c---------------------+   |   
             |   +- -d---------------------+   |   
             |   +- -e---------------------+   |   
             |   +- -h---------------------+   |   
             |   +- -l---------------------+   |   
             |   +- -n---------------------+   |   
             |   +- -o---------------------+   |   
             |   +- -p---------------------+   |   
             |   +- -s---------------------+   |   
             |   +- -t---------------------+   |   
             |   +- -cl--decompressionLib--+   |   
             |   '- -co--decompressionOpts-'   |   
             +- -H-----------------------------+   
             +- -S-----------------------------+   
             '- -T-----------------------------'   

   V          |   

Command parameters

Displays all available information.
Displays results of checkbits and checksums.
-cl decompressionLib
Indicates the name of the library to be used to perform the decompression. The name must be a fully qualified path referring to a file on the server. If this parameter is not specified, DB2® will attempt to use the library stored in the image. If the backup was not compressed, the value of this parameter will be ignored. If the specified library cannot be loaded, the operation will fail.
-co decompressionOpts
Describes a block of binary data that will be passed to the initialization routine in the decompression library. DB2 will pass this string directly from the client to the server, so any issues of byte reversal or code page conversion will have to be handled by the decompression library. If the first character of the data block is '@', the remainder of the data will be interpreted by DB2 as the name of a file residing on the server. DB2 will then replace the contents of string with the contents of this file and will pass this new value to the initialization routine instead. The maximum length for string is 1024 bytes.
Displays information from the headers of DMS table space data pages.
Extracts pages from an image to a file. To extract pages, you will need an input and an output file. The default input file is called extractPage.in. You can override the default input file name by setting the DB2LISTFILE environment variable to a full path. The format of the input file is as follows:
For SMS table spaces:
  S <tbspID> <objID> <objType> <startPage> <numPages>
  1. <startPage> is an object page number that is object-relative.
For DMS table spaces:
  D <tbspID> <objType> <startPage> <numPages>
  1. <objType> is only needed if verifying DMS load copy images.
  2. <startPage> is an object page number that is pool-relative.
For log files:
   L <log num> <startPos> <numPages>
For other data (for example, initial data):
   O <objType> <startPos> <numBytes>

The default output file is extractPage.out. You can override the default output file name by setting the DB2EXTRACTFILE environment variable to a full path.

Displays media header information including the name and path of the image expected by the restore utility.
The following is a brief description of the media header parameters:
Authentication Value
Indicates the value of the Authentication type. Refer to sqlenv.h file for more information.
Backup Buffer Size
Indicates the size in bytes.
Backup Gran
Indicates the Incremental type. 0 = FULL, 16 = INCREMENTAL, 48 = DELTA.
Backup Mode
Indicates whether the backup was taken online or offline. Possible values are 0 = offline, 1 = online.
Backup Type
Indicates the type of backup. 0 = Database, 3 = Table space, 4 = Load copy.
Catalog Database Partition Number
Indicates the catalog partition number in a database with DB2 Database Partitioning Feature (DPF) enabled.
Indicates whether the backup is compressed. 0 = NO, 1 = YES.
Database Seed
An internal identifier that is assigned to a database when it is created.
DB Codeset
Indicates the Codeset that is specified when database was created.
DB Comment
Indicates the database comment specified by the user when the database was created.
DB Territory
Indicates the Territory that is specified when database was created.
Include Logs
Indicates whether logs are included in the backup image. 0 = NO, 1 = YES.
Internal identifier that is used to identify which database the log files belong to.
Number of sessions
Indicates the number of backup targets that are specified on backup command.
Indicates the Server platform in hexadecimal digits where the backup was taken. Refer to sqlmon.h file for more information.
Release ID
Identifies the release id that is used internally by DB2.
Sequence Number
Indicates the sequence number of the backup image.
Status Flags
Internal flags
System Cats inc
Indicates whether the backup includes SYSCATSPACE. 0 = NO, 1 = YES.
Displays the same information as -h but only reads the 4K media header information from the beginning of the image. It does not validate the image. This option cannot be used in combination with any other options.
Displays log file header (LFH) and mirror log file header (MFH) data.
Prompt for tape mount. Assume one tape per device.
Displays detailed information from the object headers.
Displays the number of pages of each object type. This option will not show the number of pages for all different object types if the backup was done for DMS table spaces data. It only shows the total of all pages as SQLUDMSTABLESPACEDATA. The object types for SQLUDMSLOBDATA and SQLUDMSLONGDATA will be zero for DMS table spaces.
Displays the automatic storage paths in the image.
Displays the same information as -s but does not validate the image. This option cannot be used in combination with any other options.
Displays table space details, including container information, for the table spaces in the image.
Displays the same information as -t but does not validate the image. This option cannot be used in combination with any other options.
The name of the backup image file. One or more files can be checked at a time.
  1. If the complete backup consists of multiple objects, the validation will only succeed if db2ckbkp is used to validate all of the objects at the same time.
  2. When checking multiple parts of an image, the first backup image object (.001) must be specified first.


Example 1 (on UNIX platforms)
   db2ckbkp SAMPLE.0.krodger.NODE0000.CATN0000.19990817150714.001

   [1] Buffers processed:  ## 
   [2] Buffers processed:  ##
   [3] Buffers processed:  ##
   Image Verification Complete - successful.
Example 2
   db2ckbkp -h SAMPLE2.0.krodger.NODE0000.CATN0000.19990818122909.001

           Server Database Name           -- SAMPLE2
           Server Database Alias          -- SAMPLE2
           Client Database Alias          -- SAMPLE2
           Timestamp                      -- 19990818122909
           Database Partition Number      -- 0
           Instance                       -- krodger
           Sequence Number                -- 1
           Release ID                     -- 900
           Database Seed                  -- 65E0B395
           DB Comment's Codepage (Volume) -- 0
           DB Comment (Volume)            --                               
           DB Comment's Codepage (System) -- 0
           DB Comment (System)            --                               
           Authentication Value           -- 255
           Backup Mode                    -- 0
           Include Logs                   -- 0  
           Compression                    -- 0
           Backup Type                    -- 0
           Backup Gran.                   -- 0
           Status Flags                   -- 11
           System Cats inc                -- 1
           Catalog Database Partition No. -- 0
           DB Codeset                     -- ISO8859-1
           DB Territory                   -- 
           LogID                          -- 1074717952
           LogPath                       -- /home/krodger/krodger/NODE0000/
           Backup Buffer Size             -- 4194304
           Number of Sessions             -- 1
           Platform                       -- 0

   The proper image file name would be:
   [1] Buffers processed:  ####
   Image Verification Complete - successful.

Usage notes

  1. If a backup image was created using multiple sessions, db2ckbkp can examine all of the files at the same time. Users are responsible for ensuring that the session with sequence number 001 is the first file specified.
  2. This utility can also verify backup images that are stored on tape (except images that were created with a variable block size). This is done by preparing the tape as for a restore operation, and then invoking the utility, specifying the tape device name. For example, on UNIX based systems:
       db2ckbkp -h /dev/rmt0
    and on Windows:
       db2ckbkp -d \\.\tape1
  3. If the image is on a tape device, specify the tape device path. You will be prompted to ensure it is mounted, unless option -n is given. If there are multiple tapes, the first tape must be mounted on the first device path given. (That is the tape with sequence 001 in the header).
    The default when a tape device is detected is to prompt the user to mount the tape. The user has the choice on the prompt. Here is the prompt and options: (where the device I specified is on device path /dev/rmt0)
        Please mount the source media on device /dev/rmt0. 
        Continue(c), terminate only this device(d), or abort this tool(t)? 
    The user will be prompted for each device specified, and when the device reaches the end of tape.