Hi, we use Lucene NRT replication in production. For consistent snapshots, we use SnapshotDeletionPolicy to open a snapshot, and then copy the snapshot'ed files with your tool of choice like rsync. Without a snapshot, I don't think such tools work reliably - you can copy commit metadata without the data it refers to, for example.
We've run Lucene NRT replication in production for about 4 years now. Overall very happy with it. We intentionally run a simple configuration (one indexer, N searchers) to avoid difficult problems around leader election and network partitioning. Definitely took a bit of learning, but overall we would choose this path again. It is more "hands on" than just spinning up an Elasticsearch cluster - but on the other hand our previous Elasticsearch cluster took a team just just for "care and feeding" as the cluster had split-brain issues etc. Compare to Lucene NRT replication, where a single dev and no ops people can easily manage the entire stack, since all state is on a single master node. > On Aug 25, 2025, at 8:36 AM, Adrien Grand <jpou...@gmail.com> wrote: > > Hello, > > If you can guarantee no concurrent updates while you are doing the copy, > then 3rd-party tools that replicate files such as fsync are fine. But > otherwise or if you have the choice, I would recommend to use Lucene's > built-in support for replication, which can also work if there are > concurrent updates to the index. > > What is NRTLuceneReplication? I cannot find references to it. Lucene's > replicator module does have NRT (near-realtime) support through: > https://lucene.apache.org/core/10_2_0/replicator/org/apache/lucene/replicator/nrt/package-summary.html > . > > On Mon, Aug 25, 2025 at 5:18 PM sandy A <santhoshmaddy1...@gmail.com> wrote: > >> Hi Lucene Community Team, >> >> I have a couple of queries related to Lucene replication and would >> appreciate your guidance: >> >> *Query 1:* >> Is it safe to use tools like *rsync* (on Linux) or *robocopy* (on Windows) >> for copying Lucene segment files from one server to another? >> I want to understand if there are any potential risks (e.g., partial >> copies, consistency issues) or best practices recommended for such >> approaches. >> >> *Query 2:* >> I noticed that *NRTLuceneReplication* is still marked as "in development." >> Could you please clarify why it is not yet considered production-ready? Are >> there known limitations or stability concerns that we should be aware of >> before experimenting with it? >> >> Any insights or suggestions would be really helpful. >> >> >> With Regards, >> SanthoshKumar A >> > > > -- > Adrien --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
