On Mon, Jan 14, 2019 at 7:11 AM Daniel Gryniewicz <dang@xxxxxxxxxx> wrote: > > Hi. Welcome to the community. > > On 01/14/2019 07:56 AM, David C wrote: > > Hi All > > > > I've been playing around with the nfs-ganesha 2.7 exporting a cephfs > > filesystem, it seems to be working pretty well so far. A few questions: > > > > 1) The docs say " For each NFS-Ganesha export, FSAL_CEPH uses a > > libcephfs client,..." [1]. For arguments sake, if I have ten top level > > dirs in my Cephfs namespace, is there any value in creating a separate > > export for each directory? Will that potentially give me better > > performance than a single export of the entire namespace? > > I don't believe there are any advantages from the Ceph side. From the > Ganesha side, you configure permissions, client ACLs, squashing, and so > on on a per-export basis, so you'll need different exports if you need > different settings for each top level directory. If they can all use > the same settings, one export is probably better. There may be performance impact (good or bad) with having separate exports for CephFS. Each export instantiates a separate instance of the CephFS client which has its own bookkeeping and set of capabilities issued by the MDS. Also, each client instance has a separate big lock (potentially a big deal for performance). If the data for each export is disjoint (no hard links or shared inodes) and the NFS server is expected to have a lot of load, breaking out the exports can have a positive impact on performance. If there are hard links, then the clients associated with the exports will potentially fight over capabilities which will add to request latency.) -- Patrick Donnelly _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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