Excerpts from Jay Pipes's message of 2014-01-06 08:32:13 -0800: > On Mon, 2014-01-06 at 10:10 -0500, Adam Young wrote: > > > > On 01/03/2014 11:38 PM, Xu (Simon) Chen wrote: > > > > > Hi folks, > > > > > > > > > I am having trouble with using memcache as the keystone token > > > backend. I have three keystone nodes running active/active. Each is > > > running keystone on apache (for kerberos auth). I recently switched > > > from using sql backend to memcache, while have memcached running on > > > all three of the keystone nodes. > > > > > > > This triggers a memory of htere being something wonky with > > Greenthreads, the threading override in Eventlet, and Memcached. But > > you said Apache, so I think that you are not running with > > greenthreads? > > > > There are numerous things out there about apache and memcached > > performance. For example, one article talks about filling up > > partitions, etc. > > > > > > > > > > > > > This setup would run well for a while, but then apache would start > > > to hog CPUs, and memcached would increase to 30% or so. I tried to > > > increase memcached cluster from 3 to 6 nodes, but in general the > > > performance is much worse compared to sql backend. > > Probably due to the need for replication. In order to keep it > > anywhere close to in sync, it is going to require some non-trivial > > subset of fully connectedness. > > Instead of doing replication of memcache, instead just tell your > loadbalancer to have sticky sessions, and have each keystone server have > its own dedicated memcache instance.
Whats wrong with the usual memcached hyper-scale-out method of a list of servers and hashing the key to choose one? _______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : openstack@lists.openstack.org Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
