The Apache Zookeeper is a coordination service for distributed applications, like a Google's Chubby. Many projects uses zookeeper, and we (Apache Hama) also uses zookeeper for barrier synchronization of Bulk Synchronous Parallel computing framework.
Today, I surveyed more about paxos and dynamic quorum of Zookeeper project, to renaming the class name of org.apache.hama.zookeeper.QuorumPeer. Because of documentation is not enough, I didn't know what is the meaning of quorum and the term of "quorum" was somewhat odd to me.
But, the "org.apache.hama.zookeeper.QuorumPeer" is proper name!! xD
So, what is the Quorum and why do we need a Quorum?
According to Wikipedia, Quorum is the minimum number of members of a deliberative body necessary to conduct the business of that group. Ordinarily, this is a majority of the people expected to be there, although many bodies may have a lower or higher quorum.
As you know, a Fault-Tolerant mechanism is one of the important functions of distributed system. Quorum algorithm is used to prevent the split-brain condition. When split-brain condition occurrs, according to the Quorum algorithm, zookeeper determines the "Primary Patrition" and "Secondary Partition". Then, the servers in primary group are receives and processes user's request, and the servers in secondary group are becomes read-only mode. When recovered from split-brain condition? They will be merged to one partition again. Interanally, zookeeper uses atomic broadcast protocol instead of Paxos.
음성 인공지능 분야에서 스타트업이 생각해볼 수 있는 전략은 아마 다음과 같이 3가지 정도가 있을 것이다: 독자적 Vertical 음성 인공지능 Application 구축 기 음성 플랫폼을 활용한 B2B2C 형태의 비지니스 구축 기 음성 플랫폼...
Opening the black box of Deep Neural Networks via Information - https://arxiv.org/pdf/1703.00810.pdf 지금까지 딥 러닝은 어떻게 동작하는지 이해할 수 없다고 믿어져왔다...
네이버, KT, 오라클, 그리고 잠깐의 사업을 거쳐 삼성전자에 입사한지도 2년이 지났습니다. 2016년 병신년을 뒤로하며 이번에는 꽤 색다른 도전에 나섭니다. 무슨 일이야!? 국내 O2O 숙박전문 회사 CTO로 조인합니다! 존! 나 고...