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From Mark Greene <green...@gmail.com>
Subject Re: Cassandra data loss
Date Mon, 24 May 2010 16:17:51 GMT
Ryan King actually has a very nice, short and sweet explanation that cuts
through the FUD:

http://theryanking.com/entries/2010/04/29/potential-consistency/

On Mon, May 24, 2010 at 12:01 PM, Steve Lihn <stevelihn@gmail.com> wrote:

> So if I set it up to be strongly consistent, I should have the same level
> of consistency as traditional relational DB ?
>
> On the other hand, what will happen if I set it up as eventual consistent?
> Will the data become inconsistent after a crash/reboot, similar to the case
> of asynchronous replication? Is there an automated conflict resolution
> algorithm in Cassandra (which will likely cause data loss)? Or human
> intervention is needed?
>
> Steve
>
>
> On Mon, May 24, 2010 at 11:51 AM, Joe Stump <joe@joestump.net> wrote:
>
>> This is largely FUD. Cassandra let's you choose how consistent you want
>> writes to be. The more consistency you choose, the slower the writes, but
>> it's very unlikely with high consistency that you'll lose data.
>>
>> That being said, if you write with a consistency level of 0 then, yes, you
>> could lose data. Cassandra's consistency is much like root privileges on
>> Unix systems; it gives you more than enough rope to hang yourself if you so
>> choose to.
>>
>> --Joe
>>
>>
>> On May 24, 2010, at 9:47 AM, Steve Lihn wrote:
>>
>> > I am evaluating Cassandra as a candidate for our next-gen database. One
>> of my colleagues told me that "it's not recommended to use it as your system
>> of Record because it CAN lose data". Can someone with architecture
>> understanding shed some light on under what circumstance Cassandra cluster
>> can either lose data or become inconsistent ? (a node in a cluster crashes,
>> network partitions, I/O glitches, etc.)
>> >
>> > Thanks,
>> > Steve
>>
>>
>

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