Installing ApacheSolr 4.x

Needed components
Download the latest version of apache solr from http://lucene.apache.org/solr/
Download the contrib module of apache solr from https://drupal.org/project/apachesolr
Extract the apache solr to an easy to remember location(The home folder can be a good idea).
We called that APACHE_SOLR_FOLDER Install
n the cotrib module you downloaded there is a folder called solr-conf. In the folder there a folder for the version of apache: We need the files from solr-4.x.
List of needed files:

• solrconfig.xml
• schema.xml
• protwords.txt Copy those files to APACHE_SOLR_FOLDER/example/solr/collection1/conf

If you are trying to run apachesolr using the config files from apachesolr module and you're getting the error:

solr could not load config for solrconfig.xml

And the error appears even though the file exists in the directory and it looks good and the right permissions are set...

The solution is:

• Edit the file solrconfig.xml.
• Search for the string indexConfig.
• You should see that three params are duplicated in the indexConfig section.
• Remove the duplicate lines so they will only appear once in the file:

<useCompoundFile>false</useCompoundFile>
<ramBufferSizeMB>32</ramBufferSizeMB>
<mergeFactor>10</mergeFactor>

After doing that, make sure you restart apachesolr and clearcache in drupal. Now it works!