Using BMC AMI Copy page-integrity features
For table space copies,
optionally ensures that the pages being copied have correct internal formats, are structurally undamaged, and can be used to recover your data if a recovery becomes necessary. The items checked depend on the option you select and the version of Db2 you are using.
The CHECKTSLEVEL option performs page integrity checks by identifying damaged pages during the copy process. You can then take action to repair table spaces or to recover from a prior copy. CHECKTSLEVEL also prevents undetected duplication of damaged table spaces in image copies. When a check fails,
issues a message identifying the affected page (or pages) and the nature of the integrity issue.
When you specify CHECKTSLEVEL in the COPY or COPY IMAGECOPY command of
, you can choose from three levels of page integrity checking: CHECKTSLEVEL 0, CHECKTSLEVEL 1, or CHECKTSLEVEL 2. If you specify none of these,
defaults to the value of the CHECKLVL installation option. The default for CHECKLVL is set to 0.
Additional information is available as follows:
- For the specific elements checked when the installation option default is used, see CHECKTSLEVEL in Global-COPY-options.
- For setting the CHECKLVL installation option, see Basic installation options description.
- For performance considerations, see the discussion on Page-integrity-checking-CHECKLVL.
CHECKTSLEVEL 0
CHECKTSLEVEL 0 performs standard minimal checking.
Specifically,
automatically checks the page number, the broken page indicator, the consistency of the header and trailer bytes, and the validity of the page log RBA or LRSN.
CHECKTSLEVEL 1
CHECKTSLEVEL 1 performs intrapage checks, consistency and validity checks on both segmented and nonsegmented table space maps, and also checks data page structure.
These checks are additional to those performed by CHECKTSLEVEL 0.
CHECKTSLEVEL 2
CHECKTSLEVEL 2 performs the same intrapage checks as those described for CHECKTSLEVEL 1.
It also performs interpage checks on pointer records and table segment chains and ensures the agreement of space map pages and the associated data pages. When checking catalog and directory table spaces, CHECKTSLEVEL 2 also checks hash chains and ring pointer chains.