Is there a way to implement consume acknowledgement sync when using Classic Queue in federation mode

[mmpei]

Now we are mainly using classic queue. and also we'd like to build a active-standby HA mode in two DCs.
we have read a lot, and know the federation mode by official and the another VMware designed but the second one not support classic queue.
and i also know the difficulty to sync consume acks between two clusters,

1. there is no api to get the one message and flag it.
2. there is no a file like wal to record the acks in classic queue, so it's difficult to replicate it.

so any solution?

[michaelklishin]

Federation does not propagate acknowledgement state because

• Exchange federation replicates messages to external clusters
• Queue federation moves them using a regular consumer (and client) with a low priority

Warm standby replication in VMware RabbitMQ replicates full quorum queue state. It does not support classic queues because classic queue replication will be removed in RabbitMQ 4.0 and it does not make sense to replicate a queue that's not replicated within a cluster to external clusters.

[mmpei]

Thank you michael.
Could you please give us some design suggestion or reference if we'd like to achieve active-standby mode in classic queues?