Extended consistency groups
An extended consistency group (EXCTG) is a collection of journals in multiple primary storage systems and/or multiple secondary storage systems. EXCTGs allow you to guarantee data consistency during copy operations.
With EXCTGs, you perform operations on associated journals and their pairs at the same time. Journals can be registered and removed from EXCTGs. The journals of a maximum of four different storage systems can be registered with the same EXTG. However, one journal cannot be registered with multiple EXTGs.
Note
- In the 2DC or 3DC configuration, you cannot use EXCTGs.
- You cannot register a journal that has two mirror IDs to an EXCTG.
- When a journal is registered to an EXCTG, you cannot add a second mirror ID to that journal.