Hi Patrick Thanks for the info. If I did multiple exports, how does that work in terms of the cache settings defined in ceph.conf, are those settings per CephFS client or a shared cache? I.e if I've definied client_oc_size, would that be per export?
Cheers, On Tue, Jan 15, 2019 at 6:47 PM Patrick Donnelly <pdonn...@redhat.com> wrote: > On Mon, Jan 14, 2019 at 7:11 AM Daniel Gryniewicz <d...@redhat.com> 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@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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