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From Matthew Dennis <mden...@datastax.com>
Subject Re: Data distribution
Date Tue, 15 Feb 2011 02:07:21 GMT
regardless of increasing RF or not, RR happens based on the
read_repair_chance setting.  RR happens after the request has been replied
to though, so it's possible that if you increase the RF and then read that
the read might get stale/missing data.  RR would then put the correct value
on all the correct nodes so future reads would see the correct data, but the
initial read might not.

If you are already reading at CL.ONE then after increasing the RF you need
to read at CL.Q to maintain the same consistency.  If you're reading at CL.Q
or CL.ALL, then after increasing the RF you need to read at CL.ALL to
maintain the same consistency.  You have to do this until all the nodes are
consistent again.  If you depend on RR only this time is unbounded.  If you
run repair, then after repair the repair is complete you can go back to your
original CL.

tl;dr run nodetool repair after increasing the RF

On Mon, Feb 14, 2011 at 7:52 PM, mcasandra <mohitanchlia@gmail.com> wrote:

>
> When I increase the replication factor does the repair happen automatically
> in background when client first tries to access data from the node where
> data does not exist.
>
> Or the nodetool repair need to run after increasing the replication factor.
> --
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> Sent from the cassandra-user@incubator.apache.org mailing list archive at
> Nabble.com.
>

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