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From Steve Lihn <>
Subject Re: Cassandra data loss
Date Mon, 24 May 2010 16:01:10 GMT
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?


On Mon, May 24, 2010 at 11:51 AM, Joe Stump <> 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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