: We upgraded our cluster to Solr 4.10.0 for couple days and again : reverted back to 4.8.0. However the dashboard still shows Solr 4.10.0. : Do you know why?
because you didn't fully revert - you are still running Solr 4.10.0 - the details of what steps you took to try and switch back make a huge differnet in understanding why you are still running .0 even though you don't want to. : We recently added new shards to our cluster and dashboard shows correct : Solr version (4.8.0) for these new shards. We copied index from one of : old shards (where it is showing 4.10.0 on dashboard) to this new shard : and we see this error upon start up. How do we get rid of this error? IndexFormatTooNewException means exactly what it sounds like -- you are asking Solr/Lucene to open an index that it can tell was created by a newer version of the software and it is incapable of doing so. You either need to upgrade all of the nodes to 4.10, or you need to scrap this index, do a *real* downgrade to 4.8, and then rebuild your index (or restore a backup index from before you attempted to upgrade. : Caused by: org.apache.lucene.index.IndexFormatTooNewException: Format version is not supported (resource: BufferedChecksumIndexInput(MMapIndexInput(path="/local/data/solr13/index.20140919180209018/segments_1tzz"))): 3 (needs to be between 0 and 2) : at org.apache.lucene.codecs.CodecUtil.checkHeaderNoMagic(CodecUtil.java:156) : at org.apache.lucene.index.SegmentInfos.read(SegmentInfos.java:335) : at org.apache.lucene.index.SegmentInfos$1.doBody(SegmentInfos.java:416) : at org.apache.lucene.index.SegmentInfos$FindSegmentsFile.run(SegmentInfos.java:864) : at org.apache.lucene.index.SegmentInfos$FindSegmentsFile.run(SegmentInfos.java:710) : at org.apache.lucene.index.SegmentInfos.read(SegmentInfos.java:412) : at org.apache.lucene.index.IndexWriter.<init>(IndexWriter.java:749) : : : -Hoss http://www.lucidworks.com/
