openstack team mailing list archive

[John Leach <john@xxxxxxxxxxxxxxx>]

On 12/03/12 17:42, John Dickinson wrote:
> 
> On Mar 10, 2012, at 5:58 AM, John Leach wrote:
>> 
>> I think what I need here is hierarchical zones - I'd define one
>> parent zone per data-centre, and then multiple child zones within
>> each (representing racks or whatever).
>> 
>> Swift would be configured to write 3 replicas in 3 child zones,
>> aiming for at least 1 one replica per parent zone (handing off if
>> the parent zone is unavailable).
> 
> This would be a great feature for swift, and it's very much in line
> with some things we've brainstormed about.

ah great, glad to know it's popping up on people's radars.

>> I saw an oscon 2011 swift talk slide that mentioned "layered zones"
>> as future dev work - mentioning "cabinets, not zones".
>> Extrapolating from these 5 words, this is exactly what I need, when
>> will it be ready? ;)
>> 
>> Any thoughts on this?  Can the existing Ring implementation be
>> extended to do this kind of thing? Is the code modular enough to be
>> able to make the Ring implementation pluggable?
> 
> Beyond gholt's brimring (which you looked at earlier), I don't know
> of any work that has been done on this. I certainly think that the
> existing ring can be modified to handle these use cases, but it's not
> really "pluggable" (beyond a replacement that supports the same
> methods). I'd like to see the existing ring implementation expanded
> for these use cases (and remain compatible with existing deployments)
> rather than move to a plugin/extensions/whatever model.
> 
> If you and others would like to work on these features, I think a
> large part of the swift community would gratefully accept it.

ah great, I'm currently looking at getting brimring working as a
starting point.  I can see how it might be easier to add this
functionality to the existing ring though, without swapping it out
completely.

I'll drop a line back with any progress I make.

Thanks!

John.