> Lustre runs the majority of the world's supercomputers. It seems a > little unfair to dismiss them without at least giving a reason > why. They have m

> Lustre runs the majority of the world's supercomputers. It seems a > little unfair to dismiss them without at least giving a reason > why. They have made some progress towards getting their kernel > client upstream recently. Lustre aims at performance and thus everything is in-kernel, which makes operations a nightmare: basically everything you have is an opaque filesystem structure on disk, and a bunch of logs which can be very difficult to read. And you have to run the kernel with Lustre patches, which only apply cleanly to RHEL and SLES; work is being done on getting Debian in, but still no luck with Ubuntu or recent mainstream kernels. Also, there is no clear upgrade path between different versions: the recommended procedure is to dump everything to another filesystem and then reload after the upgrade. There is no replication handled at the FS level. When running Lustre on top of ext4, you have to use the Lustre's own versions of the ext4 utilities, which replace the ext4 utilities in the system... In short: Lustre sacrified a lot of ops-friendliness for the sake of high-performance. This is quite the opposite choice that GlusterFS has made. (Edit: formatting)