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From Jonathan Shook <>
Subject Re: Seeds, autobootstrap nodes, and replication factor
Date Sat, 05 Jun 2010 01:28:33 GMT
If I may ask, why the need for frequent topology changes?

On Fri, Jun 4, 2010 at 1:21 PM, Benjamin Black <> wrote:
> On Fri, Jun 4, 2010 at 11:14 AM, Philip Stanhope <> wrote:
>> I guess I'm thick ...
>> What would be the right choice? Our data demands have already been proven to scale
beyond what RDB can handle for our purposes. We are quite pleased with Cassandra read/write/scale
out. Just trying to understand the operational considerations.
> Cassandra supports online topology changes, but those operations are
> not cheap.  If you are expecting frequent addition and removal of
> nodes from a ring, things will be very unstable or slow (or both).  As
> I already mentioned, having a large cluster (and 40 nodes qualifies
> right now) with RF=number of nodes is going to make read and write
> operations get more and more expensive as the cluster grows.  While
> you might see reasonable performance at current, small scale, it will
> not be the case when the cluster gets large.
> I am not aware of anything like Cassandra (or any other Dynamo system)
> that support such extensive replication and topology churn.  You might
> have to write it.
> b

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