A customer with a large volume of assets and site pages needs to upgrade from AEM 6.4 with MongoMK installation to AEM 6.5 MongoMK. The architect recommends reindexing and the customer wants to keep downtime in the production environment minimal during the upgrade process. Which two options would the architect choose? (Choose two.)

To reindex a large AEM MongoMK repository with minimal production downtime, the indexing process must be isolated from the live AEM author instances. This is achieved by performing the indexing on a secondary/replica member of the MongoDB replica set. Both online reindexing (B) and offline reindexing using the oak-run tool (D) can be safely executed against a replica. Once the indexing is complete on the replica, it can be promoted to primary through a failover, making the new indexes available with only a brief service interruption for the switch.

A. The doc-traversal mode is a fallback reindexing method that is significantly slower and not recommended for minimizing downtime on large repositories.
C. The crx2oak tool is used for migrating content from the legacy CRX2 repository (pre-AEM 6.0) to Oak, not for reindexing an existing Oak repository.

1. Adobe Experience Manager 6.5 Documentation, "How to Re-index in AEM 6.x". Under the "Online Re-indexing for MongoMK" section, it states: "Online re-indexing can be performed on a secondary mongo instance. This can help reduce the performance impact on your running AEM instance."

2. Adobe Experience Manager 6.5 Documentation, "Using the oak-run.jar for Indexing". The section "Offline Re-indexing for MongoMK" describes the procedure for running offline indexing against a MongoDB database, which can be a replica to minimize downtime.