Yes, for ALL, it is not good for HA, and because we meet problem when use QUORAM, and current solution is switch Write:QUORAM / Read:QUORAM when got "UnavailableException" exception.
2012/7/18 Jay Parashar <jparas...@itscape.com> > Thanks..but write ALL will fail for any downed nodes. I am thinking of > QUORAM.**** > > ** ** > > *From:* Jason Tang [mailto:ares.t...@gmail.com] > *Sent:* Tuesday, July 17, 2012 8:24 PM > *To:* user@cassandra.apache.org > *Subject:* Re: Replication factor - Consistency Questions**** > > ** ** > > Hi**** > > ** ** > > I am starting using Cassandra for not a long time, and also have problems > in consistency.**** > > ** ** > > Here is some thinking.**** > > If you have Write:Any / Read:One, it will have consistency problem, and if > you want to repair, check your schema, and check the parameter "Read repair > chance: "**** > > http://wiki.apache.org/cassandra/StorageConfiguration **** > > ** ** > > And if you want to get consistency result, my suggestion is to have > Write:ALL / Read:One, since for Cassandra, write is more faster then read. > **** > > ** ** > > For performance impact, you need to test your traffic, and if your memory > can not cache all your data, or your network is not fast enough, then yes, > it will impact to write one more node.**** > > ** ** > > BRs**** > > ** ** > > 2012/7/18 Jay Parashar <jparas...@itscape.com>**** > > Hello all, > > There is a lot of material on Replication factor and Consistency level but > I > am a little confused by what is happening on my setup. (Cassandra 1.1.2). I > would appreciate any answers. > > My Setup: A cluster of 2 nodes evenly balanced. My RF =2, Consistency > Level; > Write = ANY and Read = 1 > > I know that my consistency is Weak but since my RF = 2, I thought data > would > be just duplicated in both the nodes but sometimes, querying does not give > me the correct (or gives partial) results. In other times, it gives me the > right results > Is the Read Repair going on after the first query? But as RF = 2, data is > duplicated then why the repair? > Note: My query is done a while after the Writes so data should have been in > both the nodes. Or is this not the case (flushing not happening etc)? > > I am thinking of making the Write as 1 and Read as QUORAM so R + W > RF (1 > + > 2 > 2) to give strong consistency. Will that affect performance a lot > (generally speaking)? > > Thanks in advance > Regards > > Jay > > **** > > ** ** >
