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From sankalp kohli <kohlisank...@gmail.com>
Subject Re: Cassandra 1.2.4 - Unflushed data lost on restart
Date Fri, 06 Sep 2013 17:26:31 GMT
You should be using replication. Not all machines will power off at the
same time.
Regarding changing the fsync setting, even if you choose it to be fully
sync, there have been many studies which have shown that data was lost on
many SSDs even after fsync has returned.
So I will fix this problem by replication and not changing the fsync stuff.


On Fri, Sep 6, 2013 at 10:21 AM, Mohit Anchlia <mohitanchlia@gmail.com>wrote:

> Are you not using RF >= 3 ?
>
>
> On Fri, Sep 6, 2013 at 10:14 AM, Thapar, Vishal (HP Networking) <
> vthapar@hp.com> wrote:
>
>> My usage requirements are such that there should be least possible data
>> loss even in case of a poweroff. When you say clean shutdown do you mean
>> Cassandra service stop?
>>
>> I ran across this issue when testing out different scenarios to figure
>> out what would be best configuration for my requirements, will consider
>> batch mode as 10 seconds window might be too much for some of my use cases.
>>
>> Thanks for the reply,
>> Vishal.
>> -----------------------------------------------
>> From: Robert Coli [mailto:rcoli@eventbrite.com]
>> Sent: Friday, September 06, 2013 10:35 PM
>> To: user@cassandra.apache.org
>> Subject: Re: Cassandra 1.2.4 - Unflushed data lost on restart
>>
>> On Fri, Sep 6, 2013 at 2:42 AM, Thapar, Vishal (HP Networking) <
>> vthapar@hp.com> wrote:
>> I am running Cassandra 1.2.4 in standalone mode and see a data loss when
>> I stop/start Cassandra [kill the task].
>>
>> Clean shutdown waits for commitlog flush. Unclean shutdown does not. In
>> default periodic mode, this could mean up to 10 seconds of loss. If you
>> don't want to lose up to 10 seconds, use batch commitlog mode or... just
>> shut down cleanly?
>>
>> There are also cases in your vintage Cassandra where data in secondary
>> indexes has not been available, in case you are querying on those.
>>
>> =Rob
>>
>
>

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