The Tungsten Replicator implements open source database-neutral master/slave replication. Master/slave replication is a highly flexible technology that can solve a wide variety of problems including the following:

* Availability - Failing over to a slave database if your master database dies
* Performance Scaling - Spreading reads across many copies of data
* Cross-Site Clustering - Maintaining active database replicas across WANs 
* Change Data Capture - Extracting changes to load data warehouses or update other systems
* Zero Downtime Upgrade - Performing upgrades on a slave server which then becomes the master

Have you ever wondered how optimized your Memcached installation is? There is a common misconception that one doesn't have to think too deeply about Memcached performance, but that is not true. If your setup is inefficient, you could:

* Burn Memory
* Waste Network Round-Trips
* Store Keys That Never Get Retrieved
* Have a Low Cache Hit Ratio (i.e. query MySQL too much)
* Suffer a fate too horrible to contemplate.

Percona does a lot of consulting around Memcached, so we try to take a quantitative, scientific approach to measuring memcached performance, just like everything else we do.

The Apache Cassandra Project develops a highly scalable second-generation distributed database, bringing together Dynamo's fully distributed design and Bigtable's ColumnFamily-based data model.

Cassandra was open sourced by Facebook in 2008, where it was designed by Avinash Lakshman (one of the authors of Dynamo) and Prashant Malik. In a lot of ways you can think of Cassandra as Dynamo 2.0. Cassandra is in production use at Rackspace, Digg, and a number of other companies, but is still under heavy development.

Stalkr is a data persistence library. Stalkr enables your PHP web application to interact with database servers in a fully object-oriented pattern. No more messy SQL, no more nasty injection attacks!

This type of library is usually called an object-relational mapper, or ORM for short. However, Stalkr is different from your typical ORM. In addition to the usual “mapping” between PHP objects and SQL rows, Stalkr also boasts a wealth of scalability-friendly features, such as:

Exclusive features (of sorts: see the Yet Another ORM!? wiki page for more information)

Automatic and transparent integration with Memcached (drivers included!) Support for key-value stores, with built-in consistent hashing and redundancy (now with Redis support!) Seamless utilization of multiple clusters of potentially different database software Unique access control mechanism for additional security

Hibari is a distributed, non-relational database management system (distributed non-RDBMS) based on distributed key value store technology, implemented by Gemini Mobile Technologies, it inherits important characteristics of both the distributed non-RDBMS world and of Gemini's HyperScale® Platform.

Hibari has the following characteristics to flexibly support growing volumes of data in cloud computing space. Economic system build-up using commodity hardware Flexible, high scalability High performance and availability by consistent hashing across multiple machines High fault-tolerance by chain replication across multiple machines Safety without a single point of failure (SPOF)

Redisql is a lightweight SQL server AND Redisql is built on top of the NOSQL datastore redis, supports redis data-structures and redis commands and supports (de)normalisation of these data structures (lists,sets,hash-tables) to/from SQL tables. Redisql can also easily import/export tables to/from Mysql for Data-warehousing. Redisql is not only a data storage Swiss Army Knife, it is also extremely fast and extremely memory efficient.

Speed is achieved by being an event driven network server that stores ALL data in RAM and achieves disk persistence by using a spare cpu-core to periodically log data changes (i.e. no threads, no locks, no undo-logs, serving data over a network at RAM speed) Storage data structures w/ very low memory overhead and data compression, via algorithms w/ insignificant performance hits, greatly increase the amount of data you can fit in RAM Your hard disk's swap is utilised when your data can no longer fit in RAM. In this mode, performance is not negatively effected, if rarely-used data sits idle in swap. Redisql can use 100% of your RAM for storage and still provide disk persistence. Optimising to the SQL statements most commonly used in OLTP workloads yields a lightweight SQL server designed for low latency at high concurrency (i.e. mindblowing speed).

"Orchestrate unifies multiple databases through one simple REST API. Orchestrate runs as a service and supports queries like full-text search, events, graph, and key/value.

Orchestrate handles security, monitoring, backups, and replication. There are no licenses to buy, no software to download, no hidden costs, and no lock-in."

The MariaDB Corporation MaxScale is an intelligent proxy that allows forwarding of database statements to one or more database servers using complex rules, a semantic understanding of the database statements and the roles of the various servers within the backend cluster of databases.

MaxScale is designed to provide load balancing and high availability functionality transparently to the applications. In addition it provides a highly scalable and flexibile architecture, with plugin components to support different protocols and routing decissions.