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From Anthony John <>
Subject Re: Understand eventually consistent
Date Fri, 18 Feb 2011 18:01:54 GMT
Again, my understanding!

1. Writes will go thru w/hinted handoff, read will fail
2. Yes - but Oracle and others have no partition tolerance and lower levels
of availability. To build in partition tolerance and high availability and
still be shared nothing to avoid SPOF (to cover the RAC implementation), you
have to write on to multiple nodes and then read off multiple nodes to
ensure consistency.

You could always run RF=1 to be like most of the traditional DBMSs. The
issues you would phase are the ones that Cassandra is trying to prevent!



On Fri, Feb 18, 2011 at 11:53 AM, mcasandra <> wrote:

> I have couple of more quesitons:
> 1. What happens when RF = 3, R = 2 and W = 2 and 2 machines go down? Would
> read and write fail or get the results from that one machine that is up?
> 2. Someone in this thread mentioned that write is eventually consistent. Is
> it because response is returned to the client as soon as data is written to
> commit log. But isn't this same as other RDBMS? Oracle does the same thing
> it writes to REDO log and somepoint later does a checkpoint and flushes
> data
> to disk. But RDBMS is not called eventually consistent.
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