[DGD] just out of curiosity

[Felix A. Croes]

Ragnar Lonn <prl at gatorhole.se> wrote:

> I guess the overall question is: is DGD/Hydra a good starting point for 
> building a massively scalable, distributed state machine, or would it be 
> easier to start with something else, or completely from scratch?
>
> When you mention outbound connections, I guess you mean that state 
> distribution should be done in LPC. Would that be fast enough?

The real slowdown is going to be transmitting a message from one node to
another.  Compared to that, the overhead of LPC sending and receiving the
message will be minor.


> I want:
>
> 1. huge scalability. Up to hundreds of thousands of physical nodes where 
> each node supports hundreds of thousands of objects
> 2. a seamless world, where interaction between objects is always 
> reasonably fast from a user's point of view
> 3. reliability. A failed physical node will not cause service 
> interruptions (multiple-copy state redundancy). Multiple concurrent 
> failures can at most cause temporary interruptions (physical media state 
> backups/snapshots). Loss of data can happen, but is kept to a minimum 
> and consistency is not compromised.

You're pushing up against the boundaries of the CAP theorem.  Consistency,
Availability, Partition tolerance -- one of these you will have to forego.

Regards,
Felix Croes