Recently I encountered some problems with CDCR after we experienced network problems, I thought I'd share.
I'm using Solr 7.2.0 We have 3 solr cloud instances where we update one cloud and use cdcr to forward updates to the two solrclouds that are hosted in a cloud. Usually this works pretty well. Recently we have experienced some serious but intermittent network issues. When that occurs we find that we get tons of cdcr warnings: CdcrReplicator Failed to forward update request to target: bioreliance-catalog-assay with errors like ClassCastException, and/or NullpointerException etc... Updates accumulate on the server and it has tons of errors in the cdcr?action=errors "2018-05-18T16:11:19.860Z","internal","2018-05-18T16:11:18.860Z","internal", "2018-05-18T16:11:17.860Z","internal", When I looked around on the source collection, I found tlog files like this: -rw-r--r-- 1 apache apache 1376736 May 10 23:04 tlog.0000000000000000141.1600138985674375168 *-rw-r--r-- 1 apache apache 0 May 11 23:05 tlog.0000000000000000143.1600229645842644992* *-rw-r--r-- 1 apache apache 65458 May 12 07:50 tlog.0000000000000000142.1600229582225539072* -rw-r--r-- 1 apache apache 1355610 May 18 10:05 tlog.0000000000000000144.1600814785270644736 -rw-r--r-- 1 apache apache 1355610 May 18 10:16 tlog.0000000000000000145.1600815458585411584 -rw-r--r-- 1 apache apache 1355610 May 18 10:21 tlog.0000000000000000146.1600815785277652992 -rw-r--r-- 1 apache apache 1355610 May 18 10:29 tlog.0000000000000000147.1600816282070941696 Note the 0 length file, and the truncated file tlog.0000000000000000142.1600229582225539072 The solution is to delete these files. Once these files are removed the updates start flowing These errors show up as warnings in the log, I would have expected them to be errors. CDCR doesn't seem to be able to detect that the tlog is corrupted. Hope this helps someone else. If there are better solutions, I'd like to know -- This message and any attachment are confidential and may be privileged or otherwise protected from disclosure. If you are not the intended recipient, you must not copy this message or attachment or disclose the contents to any other person. If you have received this transmission in error, please notify the sender immediately and delete the message and any attachment from your system. Merck KGaA, Darmstadt, Germany and any of its subsidiaries do not accept liability for any omissions or errors in this message which may arise as a result of E-Mail-transmission or for damages resulting from any unauthorized changes of the content of this message and any attachment thereto. Merck KGaA, Darmstadt, Germany and any of its subsidiaries do not guarantee that this message is free of viruses and does not accept liability for any damages caused by any virus transmitted therewith. Click http://www.emdgroup.com/disclaimer <http://www.emdgroup.com/disclaimer> to access the German, French, Spanish and Portuguese versions of this disclaimer.