Cassandra: A Structured Storage System on a P2P Network

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anita

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Feb 6, 2016, 3:13:59 PM2/6/16
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Cassandra is a distributed storage system for managing structured data that is designed to scale to a very large size across many commodity servers, with no single point of failure. Reliability at massive scale is a very big challenge. Outages in the service can have significant negative impact. Hence Cassandra aims to run on top of an infrastructure of hundreds of nodes (possibly spread across different datacenters). At this scale, small and large components fail continuously; the way Cassandra manages the persistent state in the face of these failures drives the reliability and scalability of the software systems relying on this service. Cassandra has achieved several goals – scalability, high performance, high availability and applicability. In many ways Cassandra resembles a database and shares many design and implementation strategies with databases.


Data Model:
  • Every row is identified by a unique key. The key is a string and there is no limit on its size.
  • An instance of Cassandra has one table which is made up of one or more column families as defined by the user.
  • The number of column families and the name of each of the above must be fixed at the time the cluster is started. There is no limitation the number of column families but it is expected that there would be a few of these.
  • Each column family can contain one of two structures: supercolumns or columns. Both of these are dynamically created and there is no limit on the number of these that can be stored in a column family.
  • Columns are constructs that have a name, a value and a user-defined timestamp associated with them. The number of columns that can be contained in a column family is very large. Columns could be of variable number per key. For instance key K1 could have 1024 columns/super columns while key K2 could have 64 columns/super columns.
Start learning Cassandra from basics to advance levels here...
https://goo.gl/G8uXEY
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