Disclaimer : Just started NoSQL.
As per my understanding, in case of multiple nodes, 1024 V Buckets will be divided symmetrically inbetween available nodes.
On Extrapolating same distribution, How the system will behave in case 1025th Node is being added to the cluster?
Couchbase has a fixed number of vbuckets, they will always be 1024. This also means that the maximum number of nodes a couchbase cluster could have is 1024, and this 10x bigger than the biggest clusters we have so far. (Yes, some clients have clusters with ~100 nodes in it )
The advantage of sharding data into 1024 vbuckets is that you won't ever need to reshard your data (an expensive operation in mongo, for instance). It also makes couchbase super easy to scale out ( as we just need to move some buckets to the new node) and also super easy to recover from a node failure (as we just need to guarantee the correct number of replicas of each bucket)
