Solr documents lost on server restart - solr

Question

Background:
I have a Bitnami Solr image installed on Google Compute Engine
I have a custom core with a customized schema
I had updated the core with approximately 100 documents
Everything was running fine for about 3 weeks. I then decided to restart the server as a part of routine maintenance.
When I restarted, all documents in the core had disappeared. The core is empty. The core configuration is there, the schema configuration is there but the documents are gone.
I also checked the file storage area under solr/mycore/data/index and there isnt much there.
I am a Solr newbie and my usage of it is fairly simple but I am concerned that I may be doing something wrong.
Can someone please advise what could be the error?
Update:
I observed that reloading a core causes all documents in the core to be lost. So I think I may be doing something incorrect in terms of persisting documents
Update 2:
Further reading, I figured out that my autoCommit parameter in solrconfig.xml may not be set right. So I tried fiddling with it. I set maxTime to 1000 milliseconds and changed openSearcher to TRUE.
After doing the above, I tried adding a bunch of documents via the admin console and I got the below error. Am stumped now!!
auto commit error...:java.io.FileNotFoundException: /opt/bitnami/apache-solr/solr/mycore/data/index/_0.fnm (Permission denied)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(Unknown Source)
at java.io.FileOutputStream.<init>(Unknown Source)
at org.apache.lucene.store.FSDirectory$FSIndexOutput.<init>(FSDirectory.java:389)
at org.apache.lucene.store.FSDirectory.createOutput(FSDirectory.java:282)
at org.apache.lucene.store.NRTCachingDirectory.unCache(NRTCachingDirectory.java:247)
at org.apache.lucene.store.NRTCachingDirectory.sync(NRTCachingDirectory.java:182)
at org.apache.lucene.index.IndexWriter.startCommit(IndexWriter.java:4528)
at org.apache.lucene.index.IndexWriter.prepareCommitInternal(IndexWriter.java:3001)
at org.apache.lucene.index.IndexWriter.commitInternal(IndexWriter.java:3104)
at org.apache.lucene.index.IndexWriter.commit(IndexWriter.java:3071)
at org.apache.solr.update.DirectUpdateHandler2.commit(DirectUpdateHandler2.java:582)
at org.apache.solr.update.CommitTracker.run(CommitTracker.java:216)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(Unknown Source)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Answer 1

Just had a similar issue, I'm using Cloud, make sure zookeeper/conf/zoo.cfg has dataDir set to something outside of temp/ (this is used in many of the examples). temp is deleted on restart for many linux distributions.

Answer 2

Well, it seems you don't have write permissions on the disk. You should check if the OS user running your Solr instance is allowed to write on disk. Notice I don't know anything about GCE, just check if you have options for managing permissions on the file system in an administration console provided by Google.
Another option would be to move your indexes somewhere else on the file system where you have write permissions.

Answer 3

Make sure you don't have two vhosts in Catalina using the same solr home. I've found that it wipes the index on service stop.