I worked with a GlusterFS deployment in production about 2 years ago, and it was such a nightmare that I both feel compelled to write about it and never touch anything made by that team ever again.

It was the whole shebang: Kernel panics, inconsistent views, data loss, very slow performance, split-brain problems all the time. Our set up IIRC was very simple: two bricks in a replicated volume. It worked so poorly that we had to take it out of production. Some of our experience can be explained by GlusterFS performing poorly under network partitions, but nothing could justify kernel panics. It blew my mind that Redhat acquired that company and product.

Edit: I hope there's been a big improvement to the reliability and performance of GlusterFS. Can anyone with more recent experience running it in production comment?