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From Chip Childers <chip.child...@gmail.com>
Subject Re: [DISCUSS] Domain/Account/User Sync Up Among Multiple Regions
Date Sat, 09 Nov 2013 00:53:57 GMT
We are already (generally) AP for most infra changes really. I'd use that model. Eventual consistency
is better in this scenario. 

> On Nov 8, 2013, at 6:49 PM, Chiradeep Vittal <Chiradeep.Vittal@citrix.com> wrote:
> 
> I'd also like to highlight that it isn't a trivial problem.
> Let's say there's 3 regions: this means there are 3 copies of the user
> database that are geographically separated by network links that fail
> quite often (orders of magnitude more than intra-DC networks).
> 
> Here we run into the consequences of the CAP theorem [1].
> We can either have a CP or AP system: either approach makes some tradeoffs:
> 1. If we run a AP system, then the challenge is to resolve conflicting
> updates
> 2. If we run a CP system, then the challenge is to detect partitions
> reliably and disallow updates during partitions.
> 
> [1] http://en.wikipedia.org/wiki/CAP_theorem
> 
>> On 11/7/13 11:58 AM, "Chip Childers" <chipchilders@apache.org> wrote:
>> 
>> On Thu, Nov 7, 2013 at 2:37 PM, Chiradeep Vittal
>> <Chiradeep.Vittal@citrix.com> wrote:
>>> It may be an admin burden, but it has to be optional. There are other
>>> ways
>>> to achieve global sync (e.g., LDAP/AD/Oauth).
>>> A lot of service providers who run cloudstack have their own user
>>> database
>>> / portal. In their implementations the CloudStack database is not the
>>> master source of user records, but a slave.
>> 
>> +1 to it being optional.
> 

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