AAE problems

István leccine at gmail.com
Tue Jun 17 14:28:14 EDT 2014


Thanks Jordan,

Much appreciated!

I think we are good now, I deleted the AAE data and restarted the
service on one node and I am going to monitor the growth of the AAE
folder over time. See what happens.

Best regards,
Istvan

On Tue, Jun 17, 2014 at 10:48 AM, Jordan West <jwest at basho.com> wrote:
> On Tue, Jun 17, 2014 at 9:46 AM, István <leccine at gmail.com> wrote:
>
>>
>> Is there any reason to let AAE running if we don't mutate the data in
>> place?
>
>
> Yes. If your data is infrequently accessed after being written then no
> read-repair will take place. While values may not conflict, values may be
> missing (e.g. a write only successfully reached 2 of 3 nodes) or corrupt
> (bit rot on disk).
>
>>
>> Is there any way knowing what is causing the difference according to
>> AAE between two nodes?
>
>
> This information is not currently exposed, unfortunately. Given the minimal
> number of repaired keys its likely a write failed to one node or raced with
> an AAE exchange between two pairs of nodes.
>
>>
>> I was thinking about how this could potentially
>> happen and I am wondering if the Java client pb interface supports R
>> and W values, so I could make sure that a write goes in with W=(the
>> number of nodes we have).
>
>
> While this is possible, although you'd want to set W=N, where N=number of
> replicas (n_val), it will affect the performance of your writes -- although
> that may not matter given the boost from turning AAE off. In the end, it is
> the operators decision whether or not the storage and performance overhead
> of AAE is worth the added safety*. If you are frequently accessing 100% of
> your data set then there is less need to increase the W per request or use
> AAE. However, many data sets have a large amount of data that is
> infrequently accessed and the added safety is worth the cost.
>
> Hope that helps. Cheers,
> Jordan
>
> * In the upcoming Riak 2.0 release,  in order to write data to buckets w/
> the consistent property set to true enabling AAE will be required



-- 
the sun shines for all




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