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From Edward Capriolo <edlinuxg...@gmail.com>
Subject Re: sync commitlog in batch mode lose data
Date Thu, 02 Jun 2011 14:10:01 GMT
Your Losing data because at level quorm with 2 nodes becomes all.
Cassandra will not even try to write data after the node goes down .
Client should see unavailableexception. For a small window after the
failure you will see timedoutexception and those writes should hit the
commitlog.

On Wednesday, June 1, 2011, leon hong <codeblocker@gmail.com> wrote:
> wait "geili" reply
>
> 2011/6/1 Preston Chang <zhangyf2007@gmail.com>
>
> I disable the disk cache of RAID controller,  unfortunately it still lost some data.
>
> 2011/6/1 Peter Schuller <peter.schuller@infidyne.com>
>
>
>
>> 1). set commitlog sync in batch mode and the sync batch window in 0 ms
>> 2). one client wrote random keys in infinite loop with consistency level
>> QUORUM and record the keys in file after the insert() method return normally
>> 3). unplug one server (node A) power cord
>> 4). restart the server and cassandra service
>> 5). read the key list generated in step 2) with consistency level ONE
>
> How sure are you that the system is honoring fsync() properly,
> including flushing any caches on underlying drives? Or is this with
> battery backed caching RAID controllers?
>
> --
> / Peter Schuller
>
>
> --
> by Preston Chang
>
>
>
>

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