nova team mailing list archive

[Soren Hansen <soren@xxxxxxxxxx>]

On 10-09-2010 19:51, Justin Santa Barbara wrote:
> So it seems the only potential use case for Redis is public
> clouds (Rackspace), for reasons of scalability.

This has been mentioned a couple of times. I acknowledge the fact that
the NoSQL projects have excellent reputations in terms scalability, but
for Redis specifically, I just don't see it. It's got fast master-slave
replication, but you can only write to the master, and you can only have
one master, AFAICT. That doesn't sounds fantastically scalable to me, to
be honest.

> My real hope was that we would be able to have both Redis and SQL
> implementations, and we'd show that not only did Redis have all these
> problems, but we didn't get anything in return: it would be both slower
> (because of 1+N) and less scalable (because of the need to keep all the keys
> in memory); we'd then deprecate Redis.  However, we need to stay focused on
> Nova and not proving a SQL/NoSQL point - if we know what the outcome will
> be, let's just go with the right choice and not expend effort on what is
> likely to be a technical dead-end.  If someone wants to write a Redis
> back-end so that it can be benchmarked and deprecated, that's great;
> otherwise I think we should merge the patch and forget about NoSQL.
> 
> If we let Redis get into V1, then we're stuck supporting it, and we'll have
> to solve all the above problems.  I would prefer that development effort be
> focused on building IaaS, not a relational DB on top of a key-value store.

I agree completely on all of this.

-- 
Soren Hansen
Ubuntu Developer    http://www.ubuntu.com/
OpenStack Developer http://www.openstack.org/