We are experimenting with Elastic Search deployed in Azure Container Instances (Debian + OpenJDK). The ES indexes are stored into an Azure file share mounted via SMB (3.0). The Elastic Search cluster is made up of 4 nodes, each one have a separate file share to store the indices.
This configuration has been influenced by some ACIs limitations, specifically: we cannot set the max_map_count value as we do not have access to the underlying host (https://www.elastic.co/guide/en/elasticsearch/reference/current/vm-max-map-count.html). Unfortunately, this is required to run an ES cluster, therefore we were forced to use NIOF ACI’s storage is ephemera, therefore we had to map volumes to persist the indexes. ACIs only allow volume mappings using Azure File Shares, which only works with NFS or SMB. We are experiencing recurring index corruption, specifically a "read past EOF" exception. I asked on the Elastic Search forum but the answer I got was a bit generic and not really helpful other than confirming that, from ES point of view, ES should work on an SMB share as long as it behaves as a local drive. As the underlying exception relates to an issue with a Lucene index, I was wondering if you could help out? Specifically, can Lucene work on SMB? I can only find sparse information on this configuration and, while NFS seems a no-no, for SMB is not that clear. Below is the exception we are getting. java.io.IOException: read past EOF: NIOFSIndexInput(path="/bitnami/elasticsearch/data/indices/mS2bUbLtSeG0FSAMuKX7JQ/0/index/_ldsn_1.fnm") buffer: java.nio.HeapByteBuffer[pos=0 lim=1024 cap=1024] chunkLen: 1024 end: 2331: NIOFSIndexInput(path="/bitnami/elasticsearch/data/indices/mS2bUbLtSeG0FSAMuKX7JQ/0/index/_ldsn_1.fnm") at org.apache.lucene.store.NIOFSDirectory$NIOFSIndexInput.readInternal(NIOFSDirectory.java:200) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.store.BufferedIndexInput.refill(BufferedIndexInput.java:291) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.store.BufferedIndexInput.readByte(BufferedIndexInput.java:55) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.store.BufferedChecksumIndexInput.readByte(BufferedChecksumIndexInput.java:39) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.codecs.CodecUtil.readBEInt(CodecUtil.java:667) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.codecs.CodecUtil.checkHeader(CodecUtil.java:184) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.codecs.CodecUtil.checkIndexHeader(CodecUtil.java:253) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.codecs.lucene90.Lucene90FieldInfosFormat.read(Lucene90FieldInfosFormat.java:128) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.SegmentReader.initFieldInfos(SegmentReader.java:205) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.SegmentReader.<init>(SegmentReader.java:156) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.ReadersAndUpdates.createNewReaderWithLatestLiveDocs(ReadersAndUpdates.java:738) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.ReadersAndUpdates.swapNewReaderWithLatestLiveDocs(ReadersAndUpdates.java:754) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.ReadersAndUpdates.writeFieldUpdates(ReadersAndUpdates.java:678) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.ReaderPool.writeAllDocValuesUpdates(ReaderPool.java:251) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.IndexWriter.writeReaderPool(IndexWriter.java:3743) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.IndexWriter.getReader(IndexWriter.java:591) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.StandardDirectoryReader.doOpenFromWriter(StandardDirectoryReader.java:381) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.StandardDirectoryReader.doOpenIfChanged(StandardDirectoryReader.java:355) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.StandardDirectoryReader.doOpenIfChanged(StandardDirectoryReader.java:345) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.FilterDirectoryReader.doOpenIfChanged(FilterDirectoryReader.java:112) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.index.DirectoryReader.openIfChanged(DirectoryReader.java:170) ~[lucene-core-9.3.0.jar:?] at org.elasticsearch.index.engine.ElasticsearchReaderManager.refreshIfNeeded(ElasticsearchReaderManager.java:48) ~[elasticsearch-8.4.1.jar:?] at org.elasticsearch.index.engine.ElasticsearchReaderManager.refreshIfNeeded(ElasticsearchReaderManager.java:27) ~[elasticsearch-8.4.1.jar:?] at org.apache.lucene.search.ReferenceManager.doMaybeRefresh(ReferenceManager.java:167) ~[lucene-core-9.3.0.jar:?] at org.apache.lucene.search.ReferenceManager.maybeRefreshBlocking(ReferenceManager.java:240) ~[lucene-core-9.3.0.jar:?] at org.elasticsearch.index.engine.InternalEngine$ExternalReaderManager.refreshIfNeeded(InternalEngine.java:355) ~[elasticsearch-8.4.1.jar:?] at org.elasticsearch.index.engine.InternalEngine$ExternalReaderManager.refreshIfNeeded(InternalEngine.java:335) ~[elasticsearch-8.4.1.jar:?] at org.apache.lucene.search.ReferenceManager.doMaybeRefresh(ReferenceManager.java:167) ~[lucene-core-9.3.0.jar:?] Many thanks. Seb
