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From dennis zhuang <killme2...@gmail.com>
Subject Re: Could bookie server lost data between flush?
Date Mon, 28 Nov 2011 02:25:12 GMT
Thanks for your answer.
Another question about bookkeeper is that when a bookie server failed
forever(such as disk damage etc.),will bookeeper try to replicate it's
entries to other bookie server automically?Or just let it go,then some
entries will lose their replications?

在 2011年11月28日 上午10:13,Samuel Guo <guosijie@gmail.com>写道:

> Hello dennis,
>
> SyncThread only flushed Entry Logs and Index files not journal files.
>
> Step 4 only happened when entries in journal files are flushed to disk,
> which means that when bookkeeper client received responses, the entries are
> already persisted in journal files.
>
> The index may be still in Ledger Cache without being persisted when bookie
> server shuts down or crashes. But it is OK. When bookie server restarted,
> it can replay entries persisted in journal files to recover index.
>
> So no entries will be lost when bookkeeper client received their
> responses.
>
> You can read 'Data Management in Bookie Server' section in
> doc/bookkeeperOverview.textile for reference.
>
> Thanks,
> Sijie
>
> 2011/11/28 dennis zhuang <killme2008@gmail.com>
>
>> Hi,to add a entry to bookie server,it has four steps as follow:
>>
>>    1. Append the entry in *Entry Log*, return its position { logId ,
>>    offset } ;
>>    2. Update the index of this entry in *Ledger Cache* ;
>>    3. Append a transaction of update of this entry in *Journal* ;
>>    4. Respond to BookKeeper client ;
>>
>> And the EntryLogger,Journal and Index files are not forced to device
>> right now,but waiting for SyncThread to flush them.
>> My question is that bookie server would lost data between data flushs?
>>
>>
>> --
>> 庄晓丹
>> Email:        killme2008@gmail.com
>> 伯岩(花名)  boyan@taobao.com
>> Site:           http://fnil.net
>>
>> 淘宝(中国)软件有限公司 / 产品技术部 / Java中间件
>>
>>
>


-- 
庄晓丹
Email:        killme2008@gmail.com
伯岩(花名)  boyan@taobao.com
Site:           http://fnil.net

淘宝(中国)软件有限公司 / 产品技术部 / Java中间件

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