Its the number of mutations, a mutation is a collection of changes for a single row across one or more column families.
Take a look at the nodetool cfstats, this is where I assume Ops Centre is getting it's data from. Cheers ----------------- Aaron Morton Freelance Cassandra Developer @aaronmorton http://www.thelastpickle.com On 12/10/2011, at 3:44 AM, Alexandru Dan Sicoe wrote: > Hello everyone, > I was trying to get some cluster wide statistics of the total insertions > performed in my 3 node Cassandra 0.8.6 cluster. So I wrote a nice little > program that gets the CompletedTasks attribute of > org.apache.cassandra.db:type=Commitlog from every node, sums up the values > and records them in a .csv every 10 sec or so. Everything works and I get my > stats but later I found out that I am not really sure what this measure > means. I think it is the individual column insertions performed! Am I correct? > In the meantime I installed the trial version of the DataStax Operations > Center. The cluster wide dashboard, showing Writes performed as a function of > time, gives me much smaller values of the rates, compared to the measurement > I described before. The Datastax writes/sec are of the same order of > magnitude as the batch writes I perform on the cluster. But somehow I cannot > relate between this rate and the rate of my CompletedTasks measurement. > > How do people usually measure insertion rates for their custers ? Per batch, > per single columns or is actual data rate more important to know? > > Cheers, > Alexandru >
