Pants Full of Unix

It pains me to write this.

Has anybody ever done backups for Apache Lucene? (In particular, Solr, though I've no reason to believe that means anthing special for backup/recovery.) What did you do to do that, in broad strokes?

Note that I'm interested in responses in accordance with 's rules here. I do not want to know what you think might work after you google those terms. I am interested in what you already did iff (no spelling error there) you have created backups of a lucene database (index, whatever you want to call it) that were usefully recoverable.

If you don't have a real answer, please, just say nothing.