Thread:Extension talk:Lucene-search/Does an indexing server need to be a mediawiki server?

I am following the instructions to put the indexer on a different host. Let's say the original MediaWiki/Lucene host is called MW and the new index server is called IS. After installing Java, configuring stuff as documented, and copying my lucene-search directory tree from MW to IS, I start up  and get this warning:

0   [main] INFO  org.wikimedia.lsearch.util.Localization  - Reading localization for En 5    [main] WARN  org.wikimedia.lsearch.util.Localization  - Error processing message file at file:///var/www/html/w/languages/messages/MessagesEn.php java.io.FileNotFoundException: /var/www/html/w/languages/messages/MessagesEn.php (No such file or directory)

This is clearly happening because MediaWiki is not installed on index server IS. However,  starts up fine, and when I run the   script on IS, the resulting index gets properly rsync'ed to host MW. Searches on MW seem to be working fine.

My question is: does host IS also need a full MediaWiki installation on it? Or just the file tree? Or if I do neither (as above), how serious is the warning message above? Thanks.