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From aaron morton <aa...@thelastpickle.com>
Subject Re: need of regular nodetool repair
Date Wed, 11 Apr 2012 18:51:53 GMT
HH in 1.X+ is very good, but it is still an optimisation for achieving consistency. 

>> So I expect that even if I loose some HH then some other replica will reply with
data.  Is it correct?
Run a repair and see. 

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 11/04/2012, at 9:10 PM, Igor wrote:

> On 04/11/2012 12:04 PM, ruslan usifov wrote:
>> 
>> HH - this is hinted handoff?
>> 
> Yes
> 
>> 2012/4/11 Igor <igor@4friends.od.ua>
>> On 04/11/2012 11:49 AM, R. Verlangen wrote:
>> 
>> Not everything, just HH :)
>> 
>> I hope this works for me for the next reasons: I have quite large RF (6 datacenters,
each carry one replica of all dataset), read and write at CL ONE, relatively small TTL - 10
days, I have no deletes, servers almost never go down for hour. So I expect that even if I
loose some HH then some other replica will reply with data.  Is it correct?
>> 
>> Hope this works for me, but can not work for others. 
>> 
>> 
>>> Well, if everything works 100% at any time there should be nothing to repair,
however with a distributed cluster it would be pretty rare for that to occur. At least that
is how I interpret this.
>>> 
>>> 2012/4/11 Igor <igor@4friends.od.ua>
>>> BTW, I heard that we don't need to run repair if all your data have TTL, all
HH works,  and you never delete your data.
>>> 
>>> 
>>> On 04/11/2012 11:34 AM, ruslan usifov wrote:
>>>> 
>>>> Sorry fo my bad english, so QUORUM allow  doesn't make repair regularity?
But form your anser it does not follow
>>>> 
>>>> 2012/4/11 R. Verlangen <robin@us2.nl>
>>>> Yes, I personally have configured it to perform a repair once a week, as
the GCGraceSeconds is at 10 days.
>>>> 
>>>> This is also what's in the manual  http://wiki.apache.org/cassandra/Operations#Repairing_missing_or_inconsistent_data
(point 2)
>>>> 
>>>> 
>>>> 2012/4/11 ruslan usifov <ruslan.usifov@gmail.com>
>>>> Hello
>>>> 
>>>> I have follow question, if we Read and write to cassandra claster with QUORUM
consistency level, does this allow to us do not call nodetool repair regular? (i.e. every
GCGraceSeconds) 
>>>> 
>>>> 
>>>> 
>>>> -- 
>>>> With kind regards,
>>>> 
>>>> Robin Verlangen
>>>> www.robinverlangen.nl
>>>> 
>>>> 
>>> 
>>> 
>>> 
>>> 
>>> -- 
>>> With kind regards,
>>> 
>>> Robin Verlangen
>>> www.robinverlangen.nl
>>> 
>> 
>> 
> 


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