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From Brandon Williams <dri...@gmail.com>
Subject Re: URGENT HELP PLEASE!
Date Fri, 25 Mar 2011 05:05:27 GMT
On Thu, Mar 24, 2011 at 11:58 PM, Jared Laprise <jared@webonyx.com> wrote:

> My replication factor is 1
>

Then you are living dangerously.


> I haven't run repair until today, I'm using ONE for consistency level.
>

Repair at rf=1 won't do anything.

I have two servers that are load balanced (per session) which both run
> Cassandra and each server connects to Cassandra on localhost.
>
> Based on what you're saying, and being I'm using session (cookie) based
> load balancing it would be true that data is rarely read or written (per
> user) on a different server, that could be why data isn't replicating.
>
> Again, I'm extremely appreciative of your feedback as I haven't had the
> luxury of delving into all aspects of Cassandra and especially related to
> multi-node deployments. Thanks!


Here is the key point: replication_factor refers to the total replicas
(where replica means 'instance of the data', not 'copy of it'.)  You only
have one, which is why half your data disappeared when a node was down.  I
would go to 2 and then run repair (see
http://wiki.apache.org/cassandra/FAQ#change_replication) so you have
redundancy.

-Brandon

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