These are general guidelines, I've done loads of networking, but may be less familiar with SolrCloud and CDCR architecture. However, I know it's all TCP sockets, so general guidelines do apply.
Check the round-trip time between the data centers using ping or TCP ping. Throughput tests may be high, but if Solr has to wait for a response to a request before sending the next action, then just like any network protocol that does that, it will get slow. I'm pretty sure CDCR uses HTTP/HTTPS rather than just TCP, so also check whether some proxy/load balancer between data centers is causing it to be a single connection per operation. That will *kill* performance. Some proxies default to HTTP/1.0 (open, send request, server send response, close), and that will hurt. Why you should listen to me even without SolrCloud knowledge - checkout paper "Latency performance of SOAP Implementations". Same distribution of skills - I knew TCP well, but Apache Axis 1.1 not so well. I still improved response time of Apache Axis 1.1 by 250ms per call with 1-line of code. -----Original Message----- From: Tom Peters [mailto:tpet...@synacor.com] Sent: Wednesday, March 7, 2018 6:19 PM To: solr-user@lucene.apache.org Subject: CDCR performance issues I'm having issues with the target collection staying up-to-date with indexing from the source collection using CDCR. This is what I'm getting back in terms of OPS: curl -s 'solr2-a:8080/solr/mycollection/cdcr?action=OPS' | jq . { "responseHeader": { "status": 0, "QTime": 0 }, "operationsPerSecond": [ "zook01,zook02,zook03/solr", [ "mycollection", [ "all", 49.10140553500938, "adds", 10.27612635309587, "deletes", 38.82527896994054 ] ] ] } The source and target collections are in separate data centers. Doing a network test between the leader node in the source data center and the ZooKeeper nodes in the target data center show decent enough network performance: ~181 Mbit/s I've tried playing around with the "batchSize" value (128, 512, 728, 1000, 2000, 2500) and they've haven't made much of a difference. Any suggestions on potential settings to tune to improve the performance? Thanks -- Here's some relevant log lines from the source data center's leader: 2018-03-07 23:16:11.984 INFO (cdcr-replicator-207-thread-3-processing-n:solr2-a:8080_solr x:mycollection_shard1_replica_n6 s:shard1 c:mycollection r:core_node9) [c:mycollection s:shard1 r:core_node9 x:mycollection_shard1_replica_n6] o.a.s.h.CdcrReplicator Forwarded 511 updates to target mycollection 2018-03-07 23:16:23.062 INFO (cdcr-replicator-207-thread-4-processing-n:solr2-a:8080_solr x:mycollection_shard1_replica_n6 s:shard1 c:mycollection r:core_node9) [c:mycollection s:shard1 r:core_node9 x:mycollection_shard1_replica_n6] o.a.s.h.CdcrReplicator Forwarded 510 updates to target mycollection 2018-03-07 23:16:32.063 INFO (cdcr-replicator-207-thread-5-processing-n:solr2-a:8080_solr x:mycollection_shard1_replica_n6 s:shard1 c:mycollection r:core_node9) [c:mycollection s:shard1 r:core_node9 x:mycollection_shard1_replica_n6] o.a.s.h.CdcrReplicator Forwarded 511 updates to target mycollection 2018-03-07 23:16:36.209 INFO (cdcr-replicator-207-thread-1-processing-n:solr2-a:8080_solr x:mycollection_shard1_replica_n6 s:shard1 c:mycollection r:core_node9) [c:mycollection s:shard1 r:core_node9 x:mycollection_shard1_replica_n6] o.a.s.h.CdcrReplicator Forwarded 512 updates to target mycollection 2018-03-07 23:16:42.091 INFO (cdcr-replicator-207-thread-2-processing-n:solr2-a:8080_solr x:mycollection_shard1_replica_n6 s:shard1 c:mycollection r:core_node9) [c:mycollection s:shard1 r:core_node9 x:mycollection_shard1_replica_n6] o.a.s.h.CdcrReplicator Forwarded 512 updates to target mycollection 2018-03-07 23:16:46.790 INFO (cdcr-replicator-207-thread-3-processing-n:solr2-a:8080_solr x:mycollection_shard1_replica_n6 s:shard1 c:mycollection r:core_node9) [c:mycollection s:shard1 r:core_node9 x:mycollection_shard1_replica_n6] o.a.s.h.CdcrReplicator Forwarded 511 updates to target mycollection 2018-03-07 23:16:50.004 INFO (cdcr-replicator-207-thread-4-processing-n:solr2-a:8080_solr x:mycollection_shard1_replica_n6 s:shard1 c:mycollection r:core_node9) [c:mycollection s:shard1 r:core_node9 x:mycollection_shard1_replica_n6] o.a.s.h.CdcrReplicator Forwarded 512 updates to target mycollection And what the log looks like in the target: 2018-03-07 23:18:46.475 INFO (qtp1595212853-26) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067896487950&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.500 INFO (qtp1595212853-25) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067896487951&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.525 INFO (qtp1595212853-24) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067897536512&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.550 INFO (qtp1595212853-3793) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067897536513&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.575 INFO (qtp1595212853-30) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067897536514&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.600 INFO (qtp1595212853-26) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067897536515&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.625 INFO (qtp1595212853-25) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067897536516&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.651 INFO (qtp1595212853-24) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067897536517&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.676 INFO (qtp1595212853-3793) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067897536518&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 2018-03-07 23:18:46.701 INFO (qtp1595212853-30) [c:mycollection s:shard1 r:core_node2 x:mycollection_shard1_replica_n1] o.a.s.c.S.Request [mycollection_shard1_replica_n1] webapp=/solr path=/update params={_stateVer_=mycollection:30&_version_=-1594317067897536519&cdcr.update=&wt=javabin&version=2} status=0 QTime=0 This message and any attachment may contain information that is confidential and/or proprietary. 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