You want your memtables "as large as is reasonable, but not too large." Sounds like yours are too large. As a first step, I would strongly recommend upgrading to 0.6.8 and reducing the compaction priority: http://www.riptano.com/blog/cassandra-annotated-changelog-063
On Thu, Nov 25, 2010 at 12:32 PM, Carlos Alvarez <cbalva...@gmail.com> wrote: > Hello All. > > I am facing a (capacity?) problem in my eight nodes cluster running 0.6.2 > patched with CASSANDRA-1014 and CASSANDRA-699. > > I have 200 writes/second on peaks (on each node, taking into account > replication), with arow size of 35kb. I configured the memtable size to 1GB, > the biggest size my heap seems to tolerate. With this configuration, the > cluster is writing a sstable each 5 mins. > When I decrease the memtable size I run into a minor compaction storm. > However, the 1GB memtable forces me to have a hughe heap and makes me living > on the edge of the memory. > The question is: > - Do I need more power in order to write less than 1GB each five minutes? > - Has anyone experience with heaps of more than 8GBs? > - Are the standard minor compaction thresholds usually enough for high > loads? Or is something I am supposed to tune?. > > Thanks! > Carlos. > > > -- > Tal vez hubo un error en la grafía. O en la articulación del Sacro Nombre. > -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of Riptano, the source for professional Cassandra support http://riptano.com
