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Does any of our documentation say NRW are directly configurable?  It's not
really quite that simple.

N is a property of the cluster, chosen when you build the ring.
W is always a simple majority of N.
R is generally 1 (eventually consisten reads), but the client can request
it be bumped to N (> highly consistent reads) using X-Newest.

But then there's stuff like we provide RYW consistency on default reads,
which can't really be modeled by NRW notation.

- Mike



On Mon, Dec 10, 2012 at 9:47 PM, Hua ZZ Zhang <zhuadl at cn.ibm.com> wrote:

> Alex, that make sense to me.  thanks a lot. :-)
>
> *Best Regards, *
>
> ------------------------------
>
>    *Edward Zhang(张华)*
>
>
>
>
>
>
>
> [image: Inactive hide details for Alex Yang ---12/11/2012 11:37:24
> AM---Alex Yang <alex890714 at gmail.com>]Alex Yang ---12/11/2012 11:37:24
> AM---Alex Yang <alex890714 at gmail.com>
>
>
>    *Alex Yang <alex890714 at gmail.com>*
>
>    12/11/2012 11:37 AM
>
>
> To
>
>
>    Hua ZZ Zhang/China/IBM at IBMCN,
>
>
> cc
>
>
>    "openstack at lists.launchpad.net" <openstack at lists.launchpad.net>, Hai
>    HJ Ji/China/IBM at IBMCN
>
>
> Subject
>
>
>    Re: [Openstack] [swift] how to configure NWR policy
>
>
> Hi, Zhang,
> Just add 'X-Newest: Ture' in the HTTP GET request.
>
>
> 2012/12/11 Hua ZZ Zhang <*zhuadl at cn.ibm.com* <zhuadl at cn.ibm.com>>
>
>    Hi all,
>
>    I have a question about swift configuration for NWR policy. According
>    to some documents of Swift, NWR is configurable. The general configuration
>    is: N=3, W=2, R=1 or 2.
>    Swift can provide both models of consistency: strong and eventual. But
>    I can't find where to configure this option.
>
>    Any suggestion is appreciated!
>    *
>    Best Regards, *
>
>    ------------------------------
>     *Edward Zhang(张华)*
>       IBM China Software Development Lab
>
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