On Fri, Sep 19, 2014 at 5:25 PM, Sage Weil <sweil@xxxxxxxxxx> wrote: > On Fri, 19 Sep 2014, Florian Haas wrote: >> Hello everyone, >> >> Just thought I'd circle back on some discussions I've had with people >> earlier in the year: >> >> Shortly before firefly, snapshot support for CephFS clients was >> effectively disabled by default at the MDS level, and can only be >> enabled after accepting a scary warning that your filesystem is highly >> likely to break if snapshot support is enabled. Has any progress been >> made on this in the interim? >> >> With libcephfs support slowly maturing in Ganesha, the option of >> deploying a Ceph-backed userspace NFS server is becoming more >> attractive -- and it's probably a better use of resources than mapping >> a boatload of RBDs on an NFS head node and then exporting all the data >> from there. Recent snapshot trimming issues notwithstanding, RBD >> snapshot support is reasonably stable, but even so, making snapshot >> data available via NFS, that way, is rather ugly. In addition, the >> libcephfs/Ganesha approach would obviously include much better >> horizontal scalability. > > We haven't done any work on snapshot stability. It is probably moderately > stable if snapshots are only done at the root or at a consistent point in > the hierarcy (as opposed to random directories), but there are still some > basic problems that need to be resolved. I would not suggest deploying > this in production! But some stress testing woudl as always be very > welcome. :) OK, on a semi-related note: is there any reasonably current authoritative list of features that are supported and unsupported in either ceph-fuse or kernel cephfs, and if so, at what minimal version? The most comprehensive overview that seems to be available is one from Greg, which however is a year and a half old: http://ceph.com/dev-notes/cephfs-mds-status-discussion/ >> In addition, https://github.com/nfs-ganesha/nfs-ganesha/wiki/ReleaseNotes_2.0#CEPH >> states: >> >> "The current requirement to build and use the Ceph FSAL is a Ceph >> build environment which includes Ceph client enhancements staged on >> the libwipcephfs development branch. These changes are expected to be >> part of the Ceph Firefly release." >> >> ... though it's not clear whether they ever did make it into firefly. >> Could someone in the know comment on that? > > I think this is referring to the libcephfs API changes that the cohortfs > folks did. That all merged shortly before firefly. Great, thanks for the clarification. > By the way, we have some basic samba integration tests in our regular > regression tests, but nothing based on ganesha. If you really want this > to the work, the most valuable thing you could do would be to help > get the tests written and integrated into ceph-qa-suite.git. Probably the > biggest piece of work there is creating a task/ganesha.py that installs > and configures ganesha with the ceph FSAL. Hmmm, given the excellent writeup that Niels de Vos of Gluster fame wrote about this topic, I might actually be able to cargo-cult some of what's in the Samba task and adapt it for ganesha. Sorry while I'm being ignorant about Teuthology: what platform does it normally run on? I ask because I understand most of your testing is done on Ubuntu, and Ubuntu currently doesn't ship a Ganesha package, which would make the install task a bit more complex. Cheers, Florian -- 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
