David Rosenstrauch <dar...@darose.net> asked: > I'm looking for a Linux utility that will allow me to mirror/replicate a > directory tree onto each and every node in a cluster
I had to figure this out first for my home email server (pair of physical boxes) and then for a Docker swarm cluster. I've published the resulting script after years of doing this (as a plug&play docker container) at: https://github.com/instantlinux/docker-tools/tree/master/images/swarm-sync It uses unison, a package similar to rsync but works bidirectionally. I have to set up each node as a peer with one of the other members: there's not a single point of failure, but it's not quite as slick as a real clustering file system. Alas all the real-world clustering filesystems are either impractical or pricey. Of the open-source ones, I've spent weeks trying out Ceph, XtreemFS, OCFS-2, and a few others; and I ran GlusterFS for about a year. (At a past workplace, I used DRBD but concluded it's far more trouble to maintain than the benefit it offers.) GlusterFS just plain sucks, there's really nothing good at all about it: performance is beyond terrible, it won't scale, it has a tendency to silently fail (drops files randomly, and you discover it only by adding your own monitoring scripts), recovering from events often leads to a split-brain scenario, etc. Unison just-plain-works. I've never had an issue in half a decade of running it. And its performance is wire-speed. I wish it could do many-to-many clustering, but given the complexities of the clustering systems, maybe it's a good thing they never tried clustering. One-to-one peering is drop-dead simple to understand. -rich _______________________________________________ Discuss mailing list Discuss@blu.org http://lists.blu.org/mailman/listinfo/discuss