Re: 100 million columns vs 100 million rows/keys

2010-11-26 Thread Nick Telford
Prior to Cassandra 0.7, there was a limitation of 2GB on row sizes as the entire row had to fit in memory for compaction. As far as I'm aware, in Cassandra 0.7, the limit has changed to 2^31 (approximately 2 billion) columns. See http://wiki.apache.org/cassandra/CassandraLimitations for more detai

Re: Facebook messaging and choice of HBase over Cassandra - what can we learn?

2010-11-22 Thread Nick Telford
Provided at least one node receives the write, it will eventually be written to all replicas. A failure to meet the requested ConsistencyLevel is just that; not a failure to write the data itself. Once the write is received by a node, it will eventually reach all replicas, there is no roll back. T

Re: SSD vs. HDD

2010-11-05 Thread Nick Telford
.com/docs/0.6.5/operations/tuning <http://www.riptano.com/docs/0.6.5/operations/tuning>Regards, Nick Telford On 4 November 2010 22:20, Alaa Zubaidi wrote: > Thanks for the advise... > We are running on Windows, and I just added more memory to my system, 16G I > will run the test

Re: SSD vs. HDD

2010-11-04 Thread Nick Telford
If you're bottle-necking on read I/O making proper use of Cassandras key cache and row cache will improve things dramatically. A little maths using the numbers you've provided tells me that you have about 80GB of "hot" data (data valid in a 4 hour period). That's obviously too much to directly cac

Re: Consistency issue

2010-09-03 Thread Nick Telford
; > On 9/3/2010 1:51 PM, Nick Telford wrote: > > Which ConsistencyLevels did you use for your batchMutate() and getSlice() > operations? > > ConsistencyLevels directly dictate the level of consistency you will get > with your data. > > Regards, > > Nick Telford &

Re: Consistency issue

2010-09-03 Thread Nick Telford
Which ConsistencyLevels did you use for your batchMutate() and getSlice() operations? ConsistencyLevels directly dictate the level of consistency you will get with your data. Regards, Nick Telford On 3 September 2010 12:03, Hugo wrote: > Hi, > > I'm performing tests with C