This is a good source on Cassandra + write amplification: http://www.slideshare.net/rbranson/cassandra-and-solid-state-drives
2016-03-10 9:57 GMT-03:00 Benjamin Lerer <benjamin.le...@datastax.com>: > 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 > > > > > > > > >
