Resetting modified page indicators (RESETMOD)
If you use RESETMOD YES (either in the COPY statement syntax or in the RESETMOD installation option value),
BMC AMI Copy
updates each space map to clear all of the modified-page indicators .Updating each space map to clear all of the modified-page indicator incurs overhead that can degrade performance.
The modified-page indicators are useful only when you make standard incremental copies, that is, copies such as those made by the IBM Db2 COPY utility. IBM Db2 COPY uses the indicators to determine which pages to include in an incremental copy. BMC AMI Copy also uses the indicators in the same way when using the READTYPE RANDOM and CUMULATIVE YES (either in the COPY command syntax or by default). However, BMC AMI Copy provides an alternative proprietary technique that does not use the indicators when READTYPE FULLSCAN or CUMULATIVE NO are used. In these cases, the indicators need never be reset to make incremental copies.
We recommend you use RESETMOD NO for all incremental copies and RESETMOD NO if you make only full image copies (that is, no incremental copies). The value of RESETMOD used for full copies when you use incremental copies, depends on other factors. Refer to RESETMOD for more information.
With RESETMOD NO and CUMULATIVE YES, you can create merged incremental copies. Refer to Merging-incremental-copies.