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From "B. Todd Burruss" <bto...@gmail.com>
Subject Re: 1.1.1 is "repair" still needed ?
Date Thu, 11 Oct 2012 15:18:10 GMT
as of 1.0 (CASSANDRA-2034) hints are generated for nodes that timeout.

On Thu, Oct 11, 2012 at 3:55 AM, Watanabe Maki <watanabe.maki@gmail.com> wrote:
> Even if HH works fine, HH will not be created until the failure detector marks  the node
is dead.
> HH will not be created for partially timeouted mutation request ( but meets CL ) also...
In my understanding...
>
>
> On 2012/10/11, at 5:55, Rob Coli <rcoli@palominodb.com> wrote:
>
>> On Tue, Oct 9, 2012 at 12:56 PM, Oleg Dulin <oleg.dulin@gmail.com> wrote:
>>> My understanding is that the repair has to happen within gc_grace period.
>>> [ snip ]
>>> So the question is, is this still needed ? Do we even need to run nodetool
>>> repair ?
>>
>> If Hinted Handoff works in your version of Cassandra, and that version
>> is > 1.0, you "should" not need to repair if no node has crashed or
>> been down for longer than max_hint_window_in_ms. This is because after
>> 1.0, any failed write to a remote replica results in a hint, so any
>> DELETE should eventually be fully replicated.
>>
>> However hinted handoff is meaningfully broken between 1.1.0 and 1.1.6
>> (unreleased) so you cannot rely on the above heuristic for
>> consistency. In these versions, you have to repair (or read repair
>> 100% of keys) once every GCGraceSeconds to prevent the possibility of
>> zombie data. If it were possible to repair on a per-columnfamily
>> basis, you could get a significant win by only repairing
>> columnfamilies which take DELETE traffic.
>>
>> https://issues.apache.org/jira/browse/CASSANDRA-4772
>>
>> =Rob
>>
>> --
>> =Robert Coli
>> AIM&GTALK - rcoli@palominodb.com
>> YAHOO - rcoli.palominob
>> SKYPE - rcoli_palominodb

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