Siebel CGW Active-Active HA: ZooKeeper Oracle Quorum (2-node, 2-DC) vs. Classic 3+2+2 Quorum (3-DC)

Hello Oracle Community,

We are in the design phase of migrating our Siebel CRM deployment (26.3) to a true Active-Active architecture. Our current production environment runs a standard 3-node Siebel Gateway (CGW) cluster per site — HQ and DR — operating in isolation, which satisfies ZooKeeper quorum requirements independently. The new target architecture must span sites and survive a full data center outage without manual intervention.

We have narrowed the design down to two competing approaches and are seeking guidance from those with hands-on Siebel CGW clustering experience before committing to either.

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OPTION A — 2-DC Deployment with ZooKeeper Oracle Quorum
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Topology: 1 CGW node in DC1 + 1 CGW node in DC2 (2-node ZooKeeper ensemble)