For my thesis I am going to test the scalability/performance of the Elasticsearch cluster depending on the number of nodes.
I have a physical server (with 8 cores, 30 GB memory) and on that physical server I create* 4 virtual machines*, each assigned with 2 cores and 4GB of memory. On each virtual machine I install Elasticsearch, therefore each machine represents a separate node in my Elasticsearch cluster. The data contains* about 7 million documents*, I have* 5 shards and replication_count=1 (default configuration)*. I am executing a set of tests on the cluster with different cluster-configurations. At first I assign only 1 node to the cluster and execute the tests, then I assign 2 nodes to the cluster and execute the same tests again, then 3 nodes etc. The tests do not contain any fancy features (no facets, highlighting, etc), but only filters and queries. I expected that for each additional node in the cluster I would get a linear improvement of the query response time. Because each node contains a bit of the data (shard) and so the query could be executed on each shard at the same time. But it turns out that the response time of the query is not improving nor is it getting worse, *it almost stays the same*.... So my question: Are these results expected, that *the query response time does NOT improve when adding an additional node?* I execute the test queries one after another and not in parallel. Is Elasticsearch made just to handle a high load of requests, but not for improving the query time of a single request when I add additional nodes to the cluster? I mean, would I see only an improvement for each additional node, when I would run the tests in _parallel_, because then the query load is distributed? Regards, Herbert -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/elasticsearch/5d210ab6-08c0-4512-a6ee-fff677ae7207%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
