[DGD] just out of curiosity

[Schmidt, Stephen]

I have a sense that there's a conflict between this vision of a large
distributed system, and the vision of community-based creation, as
Ragner mentioned earlier. Effective communities don't scale well,
which is why LPMuds (my experience anyway) rarely went much
over a few hundred regular users, usually less. Also, communities
have to get started, so it has to be relatively easy for someone to
open a new site out of the box. People who can set up and run a
large distributed system are few and far between. If it's easy enough
to open a site that lots of people can do it, then you're going to have
a lot of sites to choose from and few of them will need more computing
power than a single machine can provide.

There was an attempt in the Olde Days to split the difference, and have
a lot of small locally-run sites that were interconnected in various ways.
But if you wanted the interconnection to be more meaningful than
being able to text-message someone on another mud, then you have
to ensure some basic compatibilities between the systems, and that's
not consistent with each community developing in its own direction.
Let alone the problems of maintaining partitioning when each site is
being independently run.

To some extent, I think we might be better off trying to get to a system
where it wouldn't take too much skill to open a simple site, and work on
having lots of small sites with close-knit groups developing in their own
ways. I see that as more attractive than going the MMP route where it's
harder for any one individual to influence the development of the
community much.

Steve

________________________________________
From: dgd-bounces at dworkin.nl [dgd-bounces at dworkin.nl] on behalf of Ragnar Lonn [prl at gatorhole.se]
Sent: Tuesday, September 11, 2012 10:11 AM
To: dgd at dworkin.nl
Subject: Re: [DGD] just out of curiosity

On 09/11/2012 03:32 PM, Felix A. Croes wrote:
> Ragnar Lonn <prl at gatorhole.se> wrote:
>
>> [...]
>> The problem with DGD/Hydra, for this particular application, is that it
>> is not meant to be run in a distributed environment. Any system that is
>> not distributed will not have enough CPU cycles for anything but a small
>> world with few players. You can get away with some sharding maybe, or
>> transferring objects between different state machines, but it will be
>> messy.
> This isn't true anymore, DGD & Hydra now explicitly support outbound
> connections.  The problem of efficiently distributed servers is still
> unsolved, but DGD/Hydra can be part of the solution.

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?

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.

   /Ragnar


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