The DB2 COPY utility

COPY TABLESPACE

Name the database and table space. Optional DSNUM copies one partition or data set. LIST copies a LISTDEF of objects in one utility statement.

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COPY TABLESPACE HRDB.HRTS
     COPYDDN(SYSCOPY)
     FULL YES
     SHRLEVEL REFERENCE

JCL needs SYSIN, SYSPRINT, and the COPYDDN data set (traditional name SYSCOPY). Many shops use TEMPLATE with GDG (+1) so each copy is a new generation. The utility inserts a row in SYSIBM.SYSCOPY with DSNAME, ICTYPE, SHRLEVEL, START_RBA / PIT_RBA, TIMESTAMP, and DSNUM.

COPY INDEX

Indexes are created COPY NO by default. ALTER INDEX … COPY YES (or CREATE INDEX COPY YES) makes the index space eligible for COPY and RECOVER instead of only REBUILD INDEX. Incremental copies of indexes are not supported: if a LIST mixes a table space FULL NO with an index, COPY takes a full copy of the index and does not fail the list. A statement that names only an index with FULL NO fails.

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COPY INDEX HR.XEMP1
     COPYDDN(IXCOPY)
     FULL YES
     SHRLEVEL REFERENCE

COPYDDN and RECOVERYDDN

Both options take one or two names: primary and optional backup.

• COPYDDN(dd1, dd2) — local site image copies
• RECOVERYDDN(dd1, dd2) — recovery-site copies for disaster restart

You do not have to take local and remote copies in the same job. If remote copies are less frequent, DR recovery uses an older full copy plus more log. IBM documents that incremental COPY for a site can fail RC 8 if the full/incremental history is not aligned between local and recovery sites—take a fresh full for both, or incremental only for the site you are on.

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TEMPLATE LOC DSN HR.COPY.&DB..&TS..L.&DATE.
TEMPLATE REM DSN HR.COPY.&DB..&TS..R.&DATE.
COPY TABLESPACE HRDB.HRTS
     COPYDDN(LOC)
     RECOVERYDDN(REM)
     FULL YES SHRLEVEL REFERENCE

Full image copies

A full copy is a complete backup of the pages in the object (or partition). It is the base of every recovery chain. After LOAD LOG NO, REORG LOG NO, or other COPY-pending events, you need a full copy (or an inline COPYDDN on the utility) before the object is backup-clean. FlashCopy image copies are data-set-level full copies; they are not incremental.

Incremental image copies

FULL NO copies pages that changed since the last full or incremental copy. Space maps (when TRACKMOD YES) let COPY skip unchanged pages, which is why incrementals are faster on large, lightly updated spaces. TRACKMOD NO still produces a smaller sequential file but may scan more like a full copy.

IBM prerequisites:

• A full image copy already exists
• COPY-pending is not on
• The last copy did not use the CONCURRENT option

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COPY TABLESPACE DSN8D12A.DSN8S12E
     FULL NO
     SHRLEVEL CHANGE

MERGECOPY later merges incrementals into a new full copy so RECOVER does not need a long incremental chain. Some catalog/directory objects always force a full copy.

SHRLEVEL options

REFERENCE drains writers so SELECT can run but UPDATE cannot. It is the copy you want if you plan to RECOVER TOCOPY / TOLASTCOPY. CHANGE claims the read class so inserts and updates continue; do not treat the data set as a crash-consistent instant. CONCURRENT (DFSMSdss concurrent copy) has extra page-size versus CI-size rules: SHRLEVEL CHANGE is not allowed for some large page sizes when the CI does not match.

A DELETE without WHERE on a segmented space is a documented exception that can conflict with COPY SHRLEVEL CHANGE—know that restriction before you schedule overnight copies during batch.

JCL sketch

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//COPYTS  EXEC DSNUPROC,SYSTEM=DB2T,UID='HR.COPY.HRTS'
//SYSCOPY DD DSN=HR.COPY.HRTS(+1),DISP=(NEW,CATLG,DELETE),
//           UNIT=SYSDA,SPACE=(CYL,(50,10),RLSE)
//SYSPRINT DD SYSOUT=*
//SYSIN    DD *
  COPY TABLESPACE HRDB.HRTS
       COPYDDN(SYSCOPY)
       FULL YES
       SHRLEVEL REFERENCE
/*

REPORT RECOVERY and a SELECT from SYSIBM.SYSCOPY are how you verify the copy landed before you need it. The RECOVER utility page shows how those SYSCOPY rows are consumed.

Explain It Like I'm Five

COPY is taking a photograph of the classroom. A full photo shows every desk. An incremental photo shows only desks that changed since the last picture. COPYDDN is the album you keep at school; RECOVERYDDN is the album you mail to the backup school. SHRLEVEL REFERENCE means “nobody move while I take the picture.” SHRLEVEL CHANGE means “keep playing; the photo might show a kid in two places.” RECOVER later uses the album plus the diary (the log) to rebuild the room.

Exercises

1. Write COPY FULL YES SHRLEVEL REFERENCE for a table space with a GDG COPYDDN.
2. List three reasons FULL NO would be rejected.
3. Explain when you would add RECOVERYDDN in the same job versus a later COPYTOCOPY.
4. Query SYSIBM.SYSCOPY for your table space and identify ICTYPE, DSNAME, and SHRLEVEL.
5. Find an index that is COPY NO and write the ALTER needed before COPY INDEX.