cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Sasha Dolgy <>
Subject Re: Location-aware replication based on objects' access pattern
Date Wed, 06 Apr 2011 17:01:19 GMT
I use the global ring to provide quick reference data.  I don't see it
as a bottle neck because there isn't a lot of data floating around it.
 Just enough to satisfy specific use cases we have.  If the end user
needs to access the data in the US ring while in Asia via the web, I
would opt to transfer their data queries through application servers
accessing the US ring...bypassing the European application servers.
You referenced craigslist earlier.  That's how I would design it ..
user clicks on Zurich but their default is Toronto ... Quick check to
the global ring to get a list of application servers for Zurich and
continue on business as usual querying the specific data for

As for replication, we are playing with Ec2Snitch now to leverage
multiple EC2 instances all over the place ... some are dedicated to
Europe, but will exist in Americas (for an extreme use case) .. while
normally we will balance between two regional sites (A / B)

Having said all that, I'll defer to the people on this list who have
much more commercial experience with it ...

On Wed, Apr 6, 2011 at 6:40 PM, Yudong Gao <> wrote:
> This is interesting. But how do you design the global ring to make
> sure that it is not the bottleneck? For example, if a client need to
> access data in the US ring, but she need to first talk to a europe
> node to get the reference data, this will not be efficient.
> Another potential problem is that the data is not synchronized among
> the rings. If one data center goes down, the data stored there will
> get lost. One way to get around may be to use the
> NetworkTopologyStrategy. For example, with RF=3, for the ring in
> europe, we can specify 2 replicas in europe and 1 replica in america.
> Thanks!
> Yudong
>> -sd

View raw message