Well, kind of hard to say anything exhaustive in a quick comment, but roughly advantages:
- POSIX compliant, including dotting the i's. As opposed to, say, NFS which isn't cache coherent.
- performance and scalability. 1 TB/s+ sequential IO to a single file is what you'd expect on a large HPC system these days.
- Metadata performance has gotten a lot better over the past decade or so, beating most(all?) other parallel filesystems.
Downsides:
- Lots of pieces in a Lustre cluster (typically nodes are paired in sort-of active/active HA configs). And lots of cables, switches etc. So a fairly decent chance something breaks every now and then.
- When something breaks, Lustre is weird and different compared to many other filesystems. Tools are rudimentary and different.
