Incremental image copies

An incremental image copy is a copy of the pages that have been changed since the last full or incremental image copy.

You cannot take an incremental image copy of an index space.

You can make an incremental image copy of a table space if the following conditions are true:

  • A full image copy of the table space exists.
  • The COPY-pending status is not on for that table space.
  • The last copy was taken without the CONCURRENT option.
  • Start of changeThe previous copy was not made by using FlashCopy®. This applies even if sequential copies were made from the FlashCopy image copy. End of change

Copy by partition or data set

You can make an incremental image copy by partition or data set (specified by DSNUM) in the following situations:

  • A full image copy of the table space exists.
  • A full image copy of the same partition or data set exists and the COPY-pending status is not on for the table space or partition.

In addition, the full image copy must have been made after the most recent use of CREATE, REORG or LOAD, or it must be an inline copy that was made during the most recent use of LOAD or REORG.

Sample control statement

To specify an incremental image copy, use FULL NO on the COPY statement, as in the following example: 
COPY TABLESPACE DSN8D10A.DSN8S10E  FULL NO   SHRLEVEL CHANGE

Performance advantage

An incremental image copy generally does not require a complete scan of the table space, with two exceptions:

  • The table space is defined with the TRACKMOD NO option.
  • You are taking the first copy after you altered a table space to TRACKMOD YES.

Space maps in each table space indicate, for each page, regardless of whether it has changed since the last image copy. Therefore, making an incremental copy can be significantly faster than making a full copy if the table space is defined with the TRACKMOD YES option. Incremental image copies of a table space that is defined with TRACKMOD NO still saves space, although the performance advantage is smaller.

Restriction: Start of changeYou cannot make incremental copies of DSNDB01.DBD01, DSNDB01.SYSDBDXA, DSNDB01.SYSUTILX, or DSNDB06.SYSCOPY in the catalog. For those objects, COPY always makes a full image copy and places the SYSCOPY record in the log.End of change