Store billions of rows with no relation I'm going to receive a large group of CSV files daily. Additionally I have 1 billion records of data (from those CSV files) but it's not a fixed number (1b records daily). They're going to be growing and I need to store them in a DB. Also there are some extra points:


There's no update
There's no join and relationship
Select a bunch of rows and group by
Write intensive is 9 times more than read (we don't need to read data it must be a storage of data)
I don't need normalisation


I had a bench between MySQL InnoDB and MyISAM. MyISAM was more better than InnoDB (because I have no normalisation) but MySQL is not a good approach because I have no relation.

Also I've checked MongoDB finally it took 50GB of data and used 150Gb of storage disk!

So I think I need a NoSQL DB which can do distributed write and support above extra points. What do you prefer?

I know I can use CSV files but I need a db approach not a file approach. I have a lot of tools and advantages like version update, bug fixes, security stuff, read and write performance, replica, etc in a database. I cannot have something like group by (or where, ...) in CSV files and I have no time to implement them with CSV files.
I did something like this with MySql and you can save directly CSV files in MySQL. I think Apache Cassandra is a good choice for you


  
  CQL3 is very similar SQL, but with some limitations that come from    the scalability (most notably: no JOINs, no aggregate functions.)
  CQL3 is now the official interface. Don't look at Thrift, unless    you're working on a legacy app. This way, you can live without
  understanding ColumnFamilies, SuperColumns, etc.
  Querying by key, or key range (secondary indices are also available)
  Tunable trade-offs for distribution and replication (N, R, W)
  Data can have expiration (set on INSERT).
  Writes can be much faster than reads (when reads are disk-bound)
  Map/reduce possible with Apache Hadoop
  All nodes are similar, as opposed to Hadoop/HBase
  Very good and reliable cross-datacenter replication
  Distributed counter datatype.
  You can write triggers in Java.
  


You see the difference between NoSQL databases here
http://kkovacs.eu/cassandra-vs-mongodb-vs-couchdb-vs-redis