Database high availability using shadow systems

Jaemyung Kim, Kenneth Salem, Khuzaima Daudjee, Ashraf Aboulnaga, Xin Pan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)


Hot standby techniques are widely used to implement highly available database systems. These techniques make use of two separate copies of the database, an active copy and a backup that is managed by the standby. The two database copies are stored independently and synchronized by the database systems that manage them. However, database systems deployed in computing clouds often have access to reliable persistent storage that can be shared by multiple servers. In this paper we consider how hot standby techniques can be improved in such settings. We present SHADOW systems, a novel approach to hot standby high availability. Like other database systems that use shared storage, SHADOWsystems push the task of managing database replication out of the database system and into the underlying storage service, simplifying the database system. Unlike other systems, SHADOW systems also provide write offloading, which frees the active database system from the need to update the persistent database. Instead, that responsibility is placed on the standby system. We present the results of a performance evaluation using a SHADOW prototype on Amazon's cloud, showing that write offloading enables SHADOWto outperform traditional hot standby replication and even a standalone DBMS that does not provide high availability.

Original languageEnglish
Title of host publicationACM SoCC 2015 - Proceedings of the 6th ACM Symposium on Cloud Computing
PublisherAssociation for Computing Machinery, Inc
Number of pages13
ISBN (Print)9781450336512
Publication statusPublished - 27 Aug 2015
Event6th ACM Symposium on Cloud Computing, ACM SoCC 2015 - Kohala Coast, United States
Duration: 27 Aug 201529 Aug 2015


Other6th ACM Symposium on Cloud Computing, ACM SoCC 2015
CountryUnited States
CityKohala Coast



  • Availability
  • Design
  • Performance

ASJC Scopus subject areas

  • Computational Theory and Mathematics
  • Theoretical Computer Science

Cite this

Kim, J., Salem, K., Daudjee, K., Aboulnaga, A., & Pan, X. (2015). Database high availability using shadow systems. In ACM SoCC 2015 - Proceedings of the 6th ACM Symposium on Cloud Computing (pp. 209-221). Association for Computing Machinery, Inc.