lucene-java-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Michael McCandless <luc...@mikemccandless.com>
Subject Re: FileNotFoundException
Date Tue, 01 Aug 2006 16:12:28 GMT

> Yes, I use the nfs mount to share the index for other search instance 
> and all the instances have same lock directory configured, but the only 
> the difference is that nfs mount is read-only mount, so I have to 
> disable the lock mechanism for search instances, only lock is enabled 
> for index modification instance. We have 6 jboss cluster for our 
> application. so 5 instances of jboss search on the same index and the 
> 6th instance used for index update.

OK unfortunately this won't work.

Well, it will "work" but you'll hit occasional FileNotFoundExceptions on 
your searchers, whenever a searcher tries to restart itself while the 
updater is writing a new segments file.

Even though the searcher's are read only, they still need to briefly 
hold the commit lock to ensure the updater doesn't write a new segments 
file while the searcher is reading it (and opening each segment).

We are working towards a fix for lock files over NFS mounts, first by 
decoupling locking from directory implementation 
(http://issues.apache.org/jira/browse/LUCENE-635) and second by creating 
better LockFactory implementations for different cases (eg at least a 
locking implementation based on native OS locks).  But this is still in 
process...

I think the best workaround for now is to take an approach like Solr:

   http://incubator.apache.org/solr/features.html
   http://incubator.apache.org/solr/tutorial.html

whereby the single writer will occasionally (at a known safe time) make 
a snapshot of its index, and then the multiple searchers can switch to 
that index once it's safe.

Mike

---------------------------------------------------------------------
To unsubscribe, e-mail: java-user-unsubscribe@lucene.apache.org
For additional commands, e-mail: java-user-help@lucene.apache.org


Mime
View raw message