Multiple image copies

In a single COPY job, you can create up to five exact copies of various data objects. Data objects include table spaces, table space partitions, data sets of a nonpartitioned table space, index spaces, and index space partitions.

You can make two sequential copies for use on the local Db2 system (installed with the option LOCALSITE), and two more for offsite recovery (on any system that is installed with the option RECOVERYSITE). You can also make a fifth FlashCopy® image copy for use on the local Db2 system. All copies are identical, and all are produced at the same time from one invocation of COPY.

Alternatively you can use COPYTOCOPY to create the needed image copies. COPYTOCOPY can be used to create sequential image copies from a FlashCopy image copy.

The ICBACKUP column in SYSIBM.SYSCOPY specifies whether the image copy data set is for the local or recovery system, and whether the image copy data set is for the primary copied data set or for the backup copied data set. The ICUNIT column in SYSIBM.SYSCOPY specifies whether the image copy data set is on tape or disk.

Remote-site recovery

For remote site recovery, Db2 assumes that the system and application libraries and the Db2 catalog and directory are identical at the local site and recovery site. You can regularly transport copies of archive logs and database data sets to a safe location to keep current data for remote-site recovery current. This information can be kept on tape until needed.

Naming the data sets for the copies

The COPYDDN option of COPY names the output data sets that receive copies for local use. The RECOVERYDDN option names the output data sets that receive copies that are intended for remote-site recovery. The options have the following formats: 

COPYDDN (ddname1,ddname2)   RECOVERYDDN (ddname3,ddname4)

The DD names for the primary output data sets are ddname1 and ddname3. The ddnames for the backup output data sets are ddname2 and ddname4.

Sample control statement

The following statement makes four full image copies of the table space DSN8S12E in database DSN8D12A. The statement uses LOCALDD1 and LOCALDD2 as DD names for the primary and backup copies that are used on the local system and RECOVDD1 and RECOVDD2 as DD names for the primary and backup copies for remote-site recovery: 

COPY TABLESPACE DSN8D12A.DSN8S12E
   COPYDDN (LOCALDD1,LOCALDD2)
   RECOVERYDDN (RECOVDD1,RECOVDD2)

You do not need to make copies for local use and for remote-site recovery at the same time. COPY allows you to use either the COPYDDN or the RECOVERYDDN option without the other. If you make copies for local use more often than copies for remote-site recovery, a remote-site recovery could be performed with an older copy, and more of the log, than a local recovery; hence, the recovery would take longer. However, in your plans for remote-site recovery, that difference might be acceptable. You can also use MERGECOPY RECOVERYDDN to create recovery-site full image copies, and merge local incremental copies into new recovery-site full copies.

Conditions for making multiple incremental image copies

Db2 cannot make incremental image copies if any of the following conditions is true:

  • The incremental image copy is requested only for a site other than the current site (the local site from which the request is made).
  • Incremental image copies are requested for both sites, but the most recent full image copy was made for only one site.
  • Incremental image copies are requested for both sites and the most recent full image copies were made for both sites, but between the most recent full image copy and current request, incremental image copies were made for the current site only.

If you attempt to make incremental image copies under any of these conditions, COPY terminates with return code 8, does not take the image copy or update the SYSIBM.SYSCOPY table, and issues the following message:

DSNU404I  csect-name
  LOCAL SITE AND RECOVERY SITE INCREMENTAL
           IMAGE COPIES ARE NOT SYNCHRONIZED

To proceed, and still keep the two sets of data synchronized, take another full image copy of the table space for both sites, or change your request to make an incremental image copy only for the site at which you are working.

Db2 cannot make an incremental image copy if the object that is being copied is an index or index space.

Maintaining copy consistency

Make full image copies for both the local and recovery sites:

  • If a table space is in COPY-pending status
  • After a LOAD or REORG procedure that did not create an inline copy
  • If an index is in the informational COPY-pending status
  • If a table space is in informational COPY-pending status

This action helps to ensure correct recovery for both local and recovery sites. If the requested full image copy is for one site only, but the history shows that copies were made previously for both sites, COPY continues to process the image copy and issues the following warning message:

DSNU406I  FULL IMAGE COPY SHOULD BE TAKEN FOR BOTH LOCAL SITE AND
           RECOVERY SITE.

The COPY-pending status of a table space is not changed for the other site when you make multiple image copies at the current site for that other site. For example, if a table space is in COPY-pending status at the current site, and you make copies from there for the other site only, the COPY-pending status is still on when you bring up the system at that other site.