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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: something bizzare occured
Date Fri, 15 Jan 2010 21:20:45 GMT
right

On Fri, Jan 15, 2010 at 3:13 PM, B. Todd Burruss <bburruss@real.com> wrote:
> so with 5 node cluster, R=W=Q and RF=3, i can only loose one consecutive
> node on the consistency "ring", correct?
>
>
> On Fri, 2010-01-15 at 12:54 -0800, Jonathan Ellis wrote:
>> it has to do w/ consistency guarantees:
>> http://wiki.apache.org/cassandra/HintedHandoff
>>
>> use quorum reads and writes instead of ALL on writes if you need both
>> consistency and availability
>>
>> -Jonathan
>>
>> On Fri, Jan 15, 2010 at 2:50 PM, B. Todd Burruss <bburruss@real.com> wrote:
>> > that makes sense, but i have had trouble understanding why
>> > hinted-handoff doesn't take care of it?  if not, how many nodes would i
>> > need to prevent this?
>> >
>> > thx
>> >
>> >
>> > On Fri, 2010-01-15 at 12:43 -0800, Jonathan Ellis wrote:
>> >> On Fri, Jan 15, 2010 at 2:39 PM, B. Todd Burruss <bburruss@real.com>
wrote:
>> >> > i'm trying to understand why cassandra 0.5 RC3 is behaving like it
is.  I
>> >> > have a 5 node cluster, RF=3, W=ALL, R=1.  all is well if all the nodes
are
>> >> > running.  if i remove a node, then "puts" fail - doesn't matter which
host
>> >> > i'm connected to.  if i restart the node, then all goes back to normal
>> >> > operation.
>> >> >
>> >> > the obvious misunderstanding to me is that i have set W=ALL.  As I
>> >> > understand it, this should mean that the data will be written to ALL
the
>> >> > replicas (RF=3) not all the nodes in the cluster.
>> >>
>> >> Right, but if you take one of the nodes down then it is going to be
>> >> one of the three replicas for 3/5 of your keys.  (Could be more
>> >> depending on your partitioner and whether you balanced your nodes.)
>> >>
>> >> > i also see the following message upon restarting the node that i stopped
-
>> >> > is it a problem?
>> >>
>> >> No.
>> >>
>> >> -Jonathan
>> >
>> >
>> >
>
>
>

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