The goal is to accelerate the reindex of indexes from an ELK cluster (version 7.6.2) composed of 3 nodes each with all the roles to a datastream in an ELK cluster (version 7.11) installed in a container system with a total of 11 nodes: 2 coordinators, 3 masters, 3 data_hot node, 3 noed data_warm
Some information about the indexes to be transferred: 189 indexes with 1 replica, a little bit more than 5 TB of data, 6 532 237 567 docs.
With the reindex function, I have already done several tests (changing the refresh interval, with / without replica, several reindexes in parallel to the same datastream, ...) and it works correctly but it takes time!
Concretely to reindex 1 index of 30 Gb, 34 731 806 docs to a datastream without replica and with a refresh_interval equal to 300s it takes about 12h to realize the transfer.
I am looking for ideas to improve the performance of this transfer.
Thanks in advance,