Actually you can't. As explained in the wiki page linked: "A hinted write does NOT count towards ConsistencyLevel requirements of ONE, QUORUM, or ALL"
For CL.QUORUM, you do need QUORUM *replicas* to be alive to answer the query. At RF=2, QUORUM=2 so no, you cannot take down any node down or (some) quorum writes/reads will result in UnavailableException. And this is not related to the number of node you have, only to the replication factor. If you want to support having a node down, you need to have RF=3. For that very reason, this is the minimum replication factor I would advise for a production cluster. -- Sylvain On Sun, Nov 28, 2010 at 6:11 PM, Jake Luciani <jak...@gmail.com> wrote: > If you read/write data with quorum then you can safely take a node down in > this scenario. Â Subsequent writes will use hinted handoff to be passed to > the node when it comes back up. > More info is here:Â http://wiki.apache.org/cassandra/HintedHandoff > > Does that answer your question? > -Jake > > On Sun, Nov 28, 2010 at 9:42 AM, Ran Tavory <ran...@gmail.com> wrote: >> >> to me it makes sense that if hinted handoff is off then cassandra cannot >> satisfy 2 out of every 3rd writes writes when one of the nodes is down since >> this node is the designated node of 2/3 writes. >> But I don't remember reading this somewhere. Does hinted handoff affect >> David's situation? >> (David, did you disable HH in your storage-config? >> <HintedHandoffEnabled>false</HintedHandoffEnabled>) >> >> On Sun, Nov 28, 2010 at 4:32 PM, David Boxenhorn <da...@lookin2.com> >> wrote: >>> >>> For the vast majority of my data usage eventual consistency is fine (i.e. >>> CL=ONE) but I have a small amount of critical data for which I read and >>> write using CL=QUORUM. >>> >>> If I have a cluster with 3 nodes and RF=2, and CL=QUORUM does that mean >>> that a value can be read from or written to any 2 nodes, or does it have to >>> be the particular 2 nodes that store the data? If it is the particular 2 >>> nodes that store the data, that means that I can't even take down one node, >>> since it will be the mandatory 2nd node for 1/3 of my data... >> >> >> >> -- >> /Ran > >
