Bigdata, Database, Hadoop

Cloud Databases & Cloud Blob…

Cloud computing is the next stage in evolution of the Internet. The cloud in cloud computing provides the means through which everything — from computing power to computing infrastructure, applications, business processes to personal collaboration — can be delivered to you as a service wherever and whenever you need. Cloud databases are web-based services, designed for running queries on structured data stored on cloud data services. Most of the time, these services work in conjunction with cloud compute resources to provide users the capability to store, process, and query data sets within the cloud environment. These services are designed to […]
Bigdata, Hadoop

SolrCloud : CAP theorem world, this makes Solr a CP system, and keep availability in certain circumstances.

A SolrCloud cluster holds one or more distributed indexes which are called Collections. Each Collection is divided into shards (to increase write capacity) and each shard has one or more replicas (to increase query capacity). One replica from each shard is elected as a leader, who performs the additional task of adding a ‘version’ to each update before streaming it to available replicas. This means that write traffic for a particular shard hits the shard’s leader first and is then synchronously replicated to all available replicas. One Solr node (a JVM instance) may host a few replicas belonging to different […]