Couchbase : 160x faster with only one node : why?

I use python client, and Couchbase server 2.2.0 community edition.

With a single node into the “cluster” : I can do 16 000 requests per second : nice !
But when there are 2 nodes into the cluster, I got only 100 requests per second for ‘set(key,val)’, and the same for ‘get(key)’ (I used the default bucket).
This is for a very small number of keys : 10 000 keys, length : only 10 bytes !

When looking the stats, it seems there is no bottleneck (CPU/disk/RAM).

My hardware :

Core i5 (3.4 Ghz)
Disk : SSD 120Go
Network : Gigabit, bandwith limited to 200 Mbps

The only point I see is that I have a 10ms latency between the 2 nodes :

  • What should be a “good” latency between nodes ?
  • What performance I can expect with a gigabit connection ?
  • I used default bucket, should I use another one with specific parameters ?

There must be something wrong here. could you send out a cbcollect_info from both nodes? I am at