memchached connections

Hi,

Is there any guidance or experiences to estimate the number of memcached connections?

Here is memcached connection on one of the 3 controllers. Connection number is the total established connections to all 3 memcached nodes.

Node 1: 10 Keystone workers have 62 connections. 11 Nova API workers have 37 connections. 6 Neutron server works have 4304 connections. 1 memcached has 4973 connections.

Node 2: 10 Keystone workers have 62 connections. 11 Nova API workers have 30 connections. 6 Neutron server works have 3703 connections. 1 memcached has 4973 connections.

Node 3: 10 Keystone workers have 54 connections. 11 Nova API workers have 15 connections. 6 Neutron server works have 6541 connections. 1 memcached has 4973 connections.

Before I increase the connection limit for memcached, I'd like to understand if all the above is expected?

How Neutron server and memcached take so many connections?

Any elaboration is appreciated.

BTW, the problem leading me here is memcached connection timeout, which results all services depending on memcached stop working properly.

Thanks! Tony