Hello,
Yes, a repository DB is necessary. It is best to use your own Innovator-C instance for this. Then the productive instance is not stressed and it remains free. The Developer Edition reaches its session limit with 3 monitored instances. Whether this is okay from a licensing point of view is debatable. Unfortunately, IBM has not yet commented on how a repository server only for InformixHQ is to be evaluated license-wise.
In my configuration (one monitored HDR pair) - I need about 4GB storage for the repository.
I hope this helps.
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Andreas Seifert
CURSOR Software AG
http://www.admin-scout.com------------------------------