Hi Marios,
The rest of the servers will handle concurrent client write queries on their copy of the index. In the end I would like to merge all the indexes.
Hm, I'm not quite sure what you want to achieve: Would you really like to join the internal index structures, or do you talk about the database, which serve as an index in your use case?
If write operations are performed on your replica servers, this probably means that you want to transfer new documents to all other servers, including your master server?
Best, Christian