> But isn't QUORUM on a 2-node cluster still 2 nodes? Yes. 3 is where you start to get some redundancy - http://thelastpickle.com/2011/06/13/Down-For-Me/
Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 20/07/2012, at 10:24 AM, Kirk True wrote: > But isn't QUORUM on a 2-node cluster still 2 nodes? > > On 07/17/2012 11:50 PM, Jason Tang wrote: >> 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 >> >> >> >> >
