I did an apple to apple comparison of WRITE speed of Mongo vs Cassandra. Benchmarking (Cluster of 4 machines. Each of 4 cores and 15gb ram. 2 IN region1 but different zones, 1 in region2 and 1 in region3. Set consistency level of 3. i.e. atleast 3 machines have to confirm of write before the write is confirmed as done to client. also fsync kept at 10 seconds ). Same specs and hardware for both mongo and cassandra.
I modified stress.py to work both for mongo and cassandra. Conclusion: Cassandra write speed is twice that of Mongo for same settings of CL and durability! Though I agree the documentation and ease of use of Mongo is much superior to Cassandra, the write speed and lesser hoops in sharding keeps the options in balance. (MongoDB needs additional Mongos server and config server. Data has to channel through the MongoS to the shards) Because Mongo is commercially backed, you would expect the edges to be smoother on that. Also CL for reads is not possible in MongoDB. So I am expecting reads too to be worse on Mongo (as I will always have to hit the primary to ensure consistency). Not tried testing yet. You also have to consider the fact 10gen can get acquired anytime. On Wed, Mar 30, 2011 at 12:55 AM, Colin <colpcl...@gmail.com> wrote: > Thank you Eric. I appreciate it. > > -----Original Message----- > From: Eric Evans [mailto:eev...@rackspace.com] > Sent: Tuesday, March 29, 2011 11:47 PM > To: user@cassandra.apache.org > Subject: Re: Ditching Cassandra > > On Tue, 2011-03-29 at 20:56 -0500, Colin wrote: >> Are you saying that 8 will or not be compatible with 7? > > You will be able to perform a rolling upgrade from 0.7.x to 0.8. That is to > say, you'll be able to upgrade each node one at a time, mixing 0.7 and 0.8 > nodes until the upgrade is complete. > >> If not, would you recommend waiting until 8? We have done an awful >> lot of work, have an awful lot of work left, and have become very >> frustrated. > > If you're interested in exploring the CQL route, and if your time-line > permits it, that's what I would do. > >> Any idea on when 8 will be available? > > Provided nothing crops up, we'll freeze on April 11th (2 weeks from > yesterday), and release on the week of May 9th (4 weeks later). > > -- > Eric Evans > eev...@rackspace.com > > >
