Structure 2010: NorthScale, a Mountain View, Calif.-based web infrastructure startup, along with social gaming giant Zynga and NHN, a South Korean search and gaming portal, are joining hands to launch Membase, a new open-source database that joins a fast growing list of NoSQL databases. Zynga and NHN, early customers of NorthScale’s Membase server, are co-sponsors and co-founders of Membase.org, which is the home of the new database offering.

Membase is a simple, fast and elastic data store that is optimized for demanding web applications. The software is based on Memcached, a very popular in-memory caching system. NorthScale was started by the leaders of the Memcached open source project. NorthScale also today announced the availability of the beta version of its NorthScale Membase Server.

Membase is joining a pretty crowded field, which includes 10Gen’s fast-growing and very popular MongoDB, which is being used by the likes of Foursquare, github and Gilt Groupe. Other NoSQL offering include CouchDB and Cassandra.

James Phillips, senior VP of products and co-founder of NorthScale, on his blog explains why Membase is a worthy entrant into the market.

Memcached is a cache (go figure). It is used to transiently cache data, in memory, spread evenly across a cluster of commodity servers. If a server fills up, memcached will eject the least recently used data object from memory to make room for “hotter” data.

Three words: simple, fast, elastic. People like memcached because it represents a practically boundless place to easily cache data, at very low cost and with predictably stellar performance. No schemas, no tables, no sharding, no normalizing, no tuning. You want to put something in memcached, you put it in there. Why put it in two places!?

Enter membase. Without ever compromising the simple, fast,elastic part, and while guaranteeing 100% on-the-wire compatibility with memcached (now, and in to the future given our direct leverage of the memcached front end code) membase adds:

* persistence – storing data to SSD and spinning media, on- or off-node
* replication – providing high availability by copying data to multiple cluster members and supporting rapid fail-over
* dynamic cluster configuration – add and remove servers, and rebalance data on a live cluster without impacting running applications

For the tens of thousands of memcached applications already running in the wild, and without changing a single line of code, membase provides a simple, fast, elastic place to store data.