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From Reynald Bourtembourg <reynald.bourtembo...@esrf.fr>
Subject Re: 回复: data loss in different DC
Date Thu, 28 Sep 2017 16:51:55 GMT
Do you mean how often we should run repairs in this situation (write at 
CL=EACH_QUORUM and CL=LOCAL_QUORUM)?

I don't consider myself as an expert in this domain, so I will let the 
real experts answer to this question...
You can also refer to this mailing list history (many threads on this 
snbject) and to the recommendations in the documentation:
http://cassandra.apache.org/doc/latest/operating/repair.html#usage-and-best-practices

Kind regards
Reynald


On 28/09/2017 14:49, Jacob Shadix wrote:
> How often are you running repairs?
>
> -- Jacob Shadix
>
> On Thu, Sep 28, 2017 at 7:53 AM, Reynald Bourtembourg 
> <reynald.bourtembourg@esrf.fr <mailto:reynald.bourtembourg@esrf.fr>> 
> wrote:
>
>     Hi,
>
>     You can write with CL=EACH_QUORUM and read with CL=LOCAL_QUORUM to
>     get strong consistency.
>
>     Kind regards,
>     Reynald
>
>
>     On 28/09/2017 13:46, Peng Xiao wrote:
>>     even with CL=QUORUM,there is no guarantee to be sure to read the
>>     same data in DC2,right?
>>     then multi DCs looks make no sense?
>>
>>
>>     ------------------ 原始邮件 ------------------
>>     *发件人:* "DuyHai Doan";<doanduyhai@gmail.com>
>>     <mailto:doanduyhai@gmail.com>;
>>     *发送时间:* 2017年9月28日(星期四) 下午5:45
>>     *收件人:* "user"<user@cassandra.apache.org>
>>     <mailto:user@cassandra.apache.org>;
>>     *主题:* Re: data loss in different DC
>>
>>     If you're writing into DC1 with CL = LOCAL_xxx, there is no
>>     guarantee to be sure to read the same data in DC2. Only repair
>>     will help you
>>
>>     On Thu, Sep 28, 2017 at 11:41 AM, Peng Xiao <2535053@qq.com
>>     <mailto:2535053@qq.com>> wrote:
>>
>>         Dear All,
>>
>>         We have a cluster with one DC1:RF=3,another DC DC2:RF=1 only
>>         for ETL,but we found that sometimes we can query records in
>>         DC1,while not able not find the same record in DC2 with
>>         local_quorum.How it happens?
>>         Could anyone please advise?
>>         looks we can only run repair to fix it.
>>
>>         Thanks,
>>         Peng Xiao
>>
>>
>
>


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