I'm really surprised you're hitting OOM errors, I suspect you have something else pathological in your system. So, I'd start checking things like - how many concurrent warming searchers you allow - How big your indexing RAM is set to (we find very little gain over 128M BTW). - Other load on your Solr server. Are you, for instance, searching on it too? - what your autocommit characterstics are (think about autocommitting fairly often with openSearcher=false). - have you defined huge caches? - .....
How big are these documents anyway? With 12G of ram, they'd have to be absolutely _huge_ to matter much. Multiple collections should work fine in ZK. I really think you have some innocent-looking configuration setting thats bollixing you up, this is not expected behavior. If at all possible, I'd also go with 4.1. I don't really think it's relevant to your situation, but there have been a lot of improvements in the code.... Best Erick
