Network engineering continued ...

This is a continuation of the earlier posts starting with this one: http://ravinote.blogspot.com/2020/09/best-practice-from-networking.html

Topology: Most networks are being deployed as new networks and often with software-defined stacks. The layout that the user might choose has to remain flexible to growth and scale to their requirements. The topology that they choose to deploy their network, might keep the edge more compute-intensive as opposed to the core of the network. This facilitates admission control and scales to any number of resources within the network.

Virtual time: As the storage server virtualizes storage over heterogeneous media and expands elastically for demand, there is a need to co-ordinate activities across participating agents. In such cases, the only event sequence that can be established correctly is the one based on virtual time.  

Gossip protocol: In a distributed environment, the best way to detect failures and determine memberships is with the help of gossip protocol. When an existing node leaves the network, it may not respond to the gossip protocol so the neighbors become aware.  The neighbors update the membership changes and copy data asynchronously. 

Paxos Algorithm: Some systems utilize a state machine replication such as Paxos that combines transaction logging for consensus with write-ahead logging for data recovery. If the state machines are replicated, they are fully Byzantine tolerant. 

Consistent hashing – Data is partitioned and replicated using consistent hashing to achieve scale and availability. Consistency is facilitated by object versioning. Replicas are maintained during updates based on a quorum like technique.