On Sun, 11 Nov 2012, Stefan Priebe wrote: > Hi Sage, > > > With btrfs, yes, although this isn't something we have tested in a while. > I'm not using btrfs as long as the devs claim it is not ready for prod. In that case, the journal is needed for consistency of the fs; we rely on writeahead journaling. It can't be turned off. Putting it on a ramdisk in this case is interesting for performance, but it means that a crash/reboot/powerloss event leaves the fs in an inconsistent and unusable state. The only time tmpfs is potentially useful in production is when you're using btrfs *and* have independent backup power sources for replicas (and can thus avoid worrying about a site-wide power failure and loss of journal). (Or have relaxed requirements for the durability of recent writes.) sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html