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 <[email protected]> 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 <[email protected]> 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 <[email protected]> > >> >> 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 > >> > > >> > > >> > > > > > > >
