Hi Jonathan,QUORUM = (sum_of_replication_factors / 2) + 1, For us Quorum = (2/2) +1 = 2.
Default CL is ONE and RF=2 with Two Nodes in the cluster.(I am little confused, what is my read CL and what is my WRITE CL?) So, does it mean that for every WRITE it will write in both the nodes? and For every READ, it will read from both nodes and give back to client? DOWNGRADERETRYPOLICY will downgrade the CL if a node is down? Regards Neha On Wed, Dec 10, 2014 at 1:00 PM, Jonathan Haddad <j...@jonhaddad.com> wrote: > > I did a presentation on diagnosing performance problems in production at > the US & Euro summits, in which I covered quite a few tools & preventative > measures you should know when running a production cluster. You may find > it useful: > http://rustyrazorblade.com/2014/09/cassandra-summit-recap-diagnosing-problems-in-production/ > > On ops center - I recommend it. It gives you a nice dashboard. I don't > think it's completely comprehensive (but no tool really is) but it gets you > 90% of the way there. > > It's a good idea to run repairs, especially if you're doing deletes or > querying at CL=ONE. I assume you're not using quorum, because on RF=2 > that's the same as CL=ALL. > > I recommend at least RF=3 because if you lose 1 server, you're on the edge > of data loss. > > > On Tue Dec 09 2014 at 7:19:32 PM Neha Trivedi <nehajtriv...@gmail.com> > wrote: > >> Hi, >> We have Two Node Cluster Configuration in production with RF=2. >> >> Which means that the data is written in both the clusters and it's >> running for about a month now and has good amount of data. >> >> Questions? >> 1. What are the best practices for maintenance? >> 2. Is OPScenter required to be installed or I can manage with nodetool >> utility? >> 3. Is is necessary to run repair weekly? >> >> thanks >> regards >> Neha >> >
