IAM Coexistence
IAM coexistence is a situation where several identity systems perform all or part of the same functions at the same time.
- Synonym
- dual-runparallel run
Definition
IAM coexistence appears frequently during migrations, acquisitions, progressive transformations, IT mergers and multi-entity architectures. It may be transitional or lasting. The questions to settle are always the same: which system is the source of truth for each data type, how repositories are synchronised, who owns each population and each application, how conflicts are arbitrated, how a user is routed to the right authentication system and — when coexistence is temporary — what the exit criteria are. Documented coexistence is an architecture pattern; unmanaged coexistence is a blind spot.
Why it matters
A poorly framed coexistence period creates entitlement discrepancies that are hard to detect and expensive to correct.
The Ariovis perspective
Coexistence is not a problem in itself. It becomes dangerous when nobody knows which system is authoritative for which decision. Healthy coexistence rests on explicit ownership; when it is transitional, it also needs written exit criteria.
Related services
Common pitfalls
- A common mistake is letting two systems be authoritative for the same attributes, producing discrepancies nobody can arbitrate.
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