DistOS 2014W Lecture 20

Cassandra

Cassandra is essentially running a BigTable interface on top of a Dynamo infrastructure. BigTable uses GFS' built-in replication and Chubby for locking. Cassandra uses gossip algorithms: Scuttlebutt. Apache Zookeeper is used for distributed configuration.

Comet

The major idea behind Comet is triggers/callbacks. There is an extensive literature in extensible operating systems, basically adding code to the operating system to better suit my application.

The presentation video of Comet

Cassandra + Cassandra is essentially running a BigTable interface on top of a Dynamo infrastructure. BigTable uses GFS' built-in replication and Chubby for locking. Cassandra uses gossip algorithms: Scuttlebutt. Apache Zookeeper is used for distributed configuration.

− Google developed its technology interbally and used for competitive advantage. +

Comet

− Facebook developed its technology in open source manner. +

− Gpl 3 you have to provide code with binary + The presentation video of Comet − In AGPL addtional service also be given with source code. + −

+ − Bigtable needs gfs.cassandra depends on server's file system.Anil feels cassndra cluster is easy to setup. + −

+ − Bigtable is designed for batch updates.cassandra is for hqbdling realtime stuff. + −

+ − Schema design is explained in inbox example.it does does not give clarity about how table will look like.Anil thinks they store lot data with messages which makes table crappy. + −

+ − Cassandra is design for high speed access and online operation. + −

+ − Zookeeper is similar to chhuby + − Zookeeper is for node level information + − Gossip is more about key partitioning + −

+ − Zookeeper is for configuration of new node. + −

+ − It writes in immutable way like functional programming.there is no assignment in functional programming.