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From "B. Todd Burruss" <bburr...@real.com>
Subject Re: quorum / hinted handoff
Date Fri, 20 Nov 2009 22:47:53 GMT
but doesn't cassandra support hinted handoff?  so if a required node is
unavailable on a write, then the next node in the ring will take the
write with a "hint" of where to put it once the node is available again.

if there isn't a "next node" then it will fail.  right?

On Fri, 2009-11-20 at 14:25 -0800, Edmond Lau wrote:
> The key is that an RF of 2 and a cluster size of 3 means that every
> piece of data is owned by 2 nodes, and the assignment of data to the 2
> nodes responsible for that data is determined by positions in the hash
> ring, not by what's up and running.  So if you have nodes A, B, and C,
> and a given key hashes to nodes A and B, then taking down either A or
> B will prevent a quorum write to those two nodes from succeeding.
> 
> Edmond
> 
> On Fri, Nov 20, 2009 at 2:14 PM, B. Todd Burruss <bburruss@real.com> wrote:
> > not really.  it seems that if i start with 3 nodes, remove 1 of them, i
> > should still have a quorum, which is 2.  this is not what i experience.
> >
> > On Fri, 2009-11-20 at 16:03 -0600, Jonathan Ellis wrote:
> >> Oh, okay.  Then it's working as expected.
> >>
> >> Does it make more sense to you now? :)
> >>
> >> -Jonathan
> >>
> >> On Fri, Nov 20, 2009 at 3:43 PM, B. Todd Burruss <bburruss@real.com> wrote:
> >> > this was on the build i got yesterday, 882359.
> >> >
> >> > ... and you are correct about if you start with 2 nodes and take one
> >> > down - there isn't a quorum and the write/read fails.  i tested that as
> >> > well.
> >> >
> >> > thx!
> >> >
> >> >
> >> > On Fri, 2009-11-20 at 15:30 -0600, Jonathan Ellis wrote:
> >> >> On Fri, Nov 20, 2009 at 11:31 AM, B. Todd Burruss <bburruss@real.com>
wrote:
> >> >> > one more point on this .. if i only start a cluster with 2 nodes,
and i
> >> >> > use the same config setup (RF=2, etc) .. it works fine.  it's
only when
> >> >> > i start with the 3 nodes and remove 1.  in fact, i remove the
node
> >> >> > before i do any reads or writes at all, completely fresh database.
> >> >>
> >> >> That sounds like a bug.  If you have 2 nodes, RF of 2, and take one
> >> >> node down then quorum anything should always fail.
> >> >>
> >> >> Is this on trunk still?
> >> >>
> >> >> -Jonathan
> >> >
> >> >
> >> >
> >
> >
> >



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