Hi,
Thanks for the quick reply. Sorry if my question was not clear. I tried to provide more
info.
________________________________
> Date: Tue, 22 Nov 2011 20:43:33 -0500
> Subject: Re: DataCenters each with their own local data source
> From: md.jahangir27@gmail.com
> To: user@cassandra.apache.org
>
> Distributing writes to all D.C.s? or reads?
Writes should be distributed within the local D.C.
Reads could be D.C. specific, or could ask a question to all D.C. instances.
>
> If each D.C. has data specific to that particular geo, why do you have
> to read from remote D.C. ?
Users want to aggregate information from different D.C.
>
> You can easily incorporate logic to re-direct operation(either
> write/read) to appropriate(local) D.C.
In the middle tier, or does Cassandra have explicit support for that?
>
> Still wondering why you want to do so?. Am assuming you want to store
> data as per I.P. (geo location data) ..Anyways, it was not very clear
> from your question what you are trying to do.
Each data center has a local data source that we can't afford to replicate across data centers.
Users may be interested in querying multiple data centers.
>
> Thanks,
> Jahangir Mohammed.
>
> On Tue, Nov 22, 2011 at 7:57 PM, Mathieu Lalonde
> <mrlalonde@live.ca<mailto:mrlalonde@live.ca>> wrote:
>
>
> Hi,
>
> I am wondering if Cassandra's features and datacenter awareness can
> help me with my scalability problems.
>
> Suppose that I have a 10-20 Data centers, each with their own local
> (massive) source of time series data. I would like:
> - to avoid replication across data centers (this seems doable based on:
> http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/Different-KeySpaces-for-different-nodes-in-the-same-ring-td5096393.html#a5096568
> )
> - writes for local data to be done on the local data center (not sure
> about that one)
> - reads from a master data center to any remote data centers (not sure
> about that one either)
>
> It sounds like I am trying to use Cassandra in a very different way
> that it was intended to be used.
> Should I simply have a middle-tier that takes care of distributing
> reads to multiple data centers and treat each data center as its own
> autonomous cluster?
>
> Thanks!
> Matt
>
>
>
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