CephFS: looking for the Swiss Army knife of POSIX filesystems

<!--HTML-->At the University of Zurich we strive to offer our researchers the best solutions to store and access their data. Last year we deployed a new Ceph cluster exclusively devoted to CephFS to replace both the traditional NFS boxes and the RBD-images-exported-over-NFS ones. The ultimate goal is to use CephFS everywhere POSIX compatibility is required, including in our (small) HPC cluster instead of a traditional parallel filesystem. We will share the benchmarks we took and the bumps we hit during the journey, navigating between releases with different maturity levels, experimental features, and performance hiccups.