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From Eric Plowe <eric.pl...@gmail.com>
Subject Re: Question about consistency
Date Wed, 09 Sep 2015 01:22:30 GMT
Rob,

All writes/reads are happening from DC1. DC2 is a backup. The web app does
not handle live requests from DC2.

Regards,

Eric Plowe

On Tuesday, September 8, 2015, Robert Coli <rcoli@eventbrite.com> wrote:

> On Tue, Sep 8, 2015 at 4:40 PM, Eric Plowe <eric.plowe@gmail.com
> <javascript:_e(%7B%7D,'cvml','eric.plowe@gmail.com');>> wrote:
>
>> I'm using Cassandra as a storage mechanism for session state persistence
>> for an ASP.NET web application. I am seeing issues where the session
>> state is persisted on one page (setting a value: Session["key"] =
>> "value" and when it redirects to another (from a post back event) and check
>> for the existence of the value that was set, it doesn't exist.
>>
>> It's a 12 node cluster with 2 data centers (6 and 6) running 2.1.9. The
>> key space that the column family lives has a RF of 3 for each data
>> center. The session state provider is using the the datastax csharp driver
>> v2.1.6. Writes and reads are at LOCAL_QUORUM.
>>
>
> 1) Write to DC_A with LOCAL_QUORUM
> 2) Replication to DC_B takes longer than it takes to...
> 3) Read from DC_B with LOCAL_QUORUM, do not see the write from 1)
>
> If you want to be able to read your writes from DC_A in DC_B, you're going
> to need to use EACH_QUORUM.
>
> =Rob
>
>

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