> ----- Original Message ----- > > From: "Poornima Gurusiddaiah" <pgurusid@xxxxxxxxxx> > > To: "Dan Lambright" <dlambrig@xxxxxxxxxx>, "Nithya Balachandran" > > <nbalacha@xxxxxxxxxx> > > Cc: "Gluster Devel" <gluster-devel@xxxxxxxxxxx> > > Sent: Tuesday, August 23, 2016 12:56:38 AM > > Subject: md-cache changes and impact on tiering > > > > Hi, > > > > The basic patches for md-cache and integrating it with cache-invalidation > > is > > merged in master. You could try master build and enable the following > > settings, to see if there is any impact on tiering performance at all: > > > > # gluster volume set <volname> performance.stat-prefetch on > > # gluster volume set <volname> features.cache-invalidation on > > # gluster volume set <volname> performance.cache-samba-metadata on > > # gluster volume set <volname> performance.md-cache-timeout 600 > > # gluster volume set <volname> features.cache-invalidation-timeout 600 To follow up on our discussions at the Berlin Gluster conference, I add to the above list one more important tunable: # gluster v set vol1 network.inode-lru-limit <large number> in my case, this was needed as the default setting was too small for my workload. I'll also share that there exists a new "inode forget" counter in gluster profile, which makes it much easier track cache utilization. With this set of tunables, I more consistently see nice improvements on small file workloads with tiering for small files. But I would imagine md-cache+upcall will help many scenarios where "lookup amplification" acts as a drag. I saw some encouraging results testing this with RDMA. Some caveats to acknowledge - client caching takes resources from the end user's machine - the md-cache timeout does not yet have an "infinity" setting; entries still age out artificially - I am running a very artificial workload using our "smallfile" workload generator [1]. It does does open/read/close over a large set of files; I've not exercised other file operations. All that said, it sure seems like a big step forward to me. Great to see small file performance improvements with gluster ! :) [1] https://github.com/bengland2/smallfile > > > > > > Note: It has to be executed in the same order. > > > > Tracker bug: https://bugzilla.redhat.com/show_bug.cgi?id=1211863 > > Patches: > > http://review.gluster.org/#/q/status:open+project:glusterfs+branch:master+topic:bug-1211863 > > > > Thanks, > > Poornima > > > _______________________________________________ Gluster-devel mailing list Gluster-devel@xxxxxxxxxxx http://www.gluster.org/mailman/listinfo/gluster-devel
