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On 28/08/14 03:41, Zane Bitter wrote:
> On 27/08/14 11:04, Steven Hardy wrote:
>> On Wed, Aug 27, 2014 at 07:54:41PM +0530, Jyoti Ranjan wrote:
>>>     I am little bit skeptical about using Swift for this use case
>>> because of
>>>     its eventual consistency issue. I am not sure Swift cluster is
>>> good to be
>>>     used for this kind of problem. Please note that Swift cluster
>>> may give you
>>>     old data at some point of time.
>>
>> This is probably not a major problem, but it's certainly worth
>> considering.
>>
>> My assumption is that the latency of making the replicas consistent
>> will be
>> small relative to the timeout for things like SoftwareDeployments, so
>> all
>> we need is to ensure that instances  eventually get the new data, act on
>
> That part is fine, but if they get the new data and then later get the
> old data back again... that would not be so good.

It would be fairly easy for the agent to check last modified headers and
ignore data which is older than the most recently fetched metadata.