Someone said the twitter blog post "Cassandra at Twitter Today" is a big blow to the reputation of Cassandra.
It is ardently discussing @http://news.ycombinator.com/item?id=1502756
Here are my comments:
1. Cassandra is very young! Especially, the design and implementation of local storage and local indexing are junior and not good.
2. Pool read-performance is also due to the poor local storage implementation.
3. The local storage, indexing and persistence structures are not stable. They need to be re-designed /re-implemented. If Twitter move data to current Cassandra, they should do another move later for a new local storage, indexing and persistence structure.
4. There are many good techniques in Cassandra and other open-sourced projects (such as Hadoop, HBase ...), etc. But, they are not ready for production. Understand the detail of these techniques and implement them in your projects/products.