Cassandra should not cause any write amplification. Write amplification appends only when you updates data on SSDs. Cassandra does not update any data in place. Data can be rewritten during compaction but it is never updated.
Benjamin On Thu, Mar 10, 2016 at 12:42 PM, Alain RODRIGUEZ <arodr...@gmail.com> wrote: > Hi Dikang, > > I am not sure about what you call "amplification", but as sizes highly > depends on the structure I think I would probably give it a try using CCM ( > https://github.com/pcmanus/ccm) or some test cluster with 'production > like' > setting and schema. You can write a row, flush it and see how big is the > data cluster-wide / per node. > > Hope this will be of some help. > > C*heers, > ----------------------- > Alain Rodriguez - al...@thelastpickle.com > France > > The Last Pickle - Apache Cassandra Consulting > http://www.thelastpickle.com > > 2016-03-10 7:18 GMT+01:00 Dikang Gu <dikan...@gmail.com>: > > > Hello there, > > > > I'm wondering is there a good way to measure the write amplification of > > Cassandra? > > > > I'm thinking it could be calculated by (size of mutations written to the > > node)/(number of bytes written to the disk). > > > > Do we already have the metrics of "size of mutations written to the > node"? > > I did not find it in jmx metrics. > > > > Thanks > > > > -- > > Dikang > > > > >
