This might only be a gotcha if you’re a lazy guy like me.
But in ordinary Solr, if you want to completely clear out your indexes, you can just delete the ‘data’ directory, no problem. It sounds weird, but several solr guru types told me I could do it, and it was certainly convenient to be able to do when my data (still in development) got all messed up and I just wanted to start over, and it did indeed work.
But when you’ve set up ‘multi core’ in Solr (which has nothing to do with CPUs, it’s solr term for having multiple entirely seperate solr indexes in one running solr process)… don’t try to just go and delete the ‘data’ directory in one of the cores. It messes everything up horribly and you have to repair/rebuild your cores.
So I guess in a solr multi-core world, if you want to delete all your solr data, you have to do it the normal way with a ‘delete’ operation.