replicationanddbm - Summary .Itcoverssetting , changes,andt

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
SQL Server Replication Summary:   This white paper describes how to use database mirroring to increase the  availability of the replication stream in a transactional environment. It covers setting  up replication in a mirrored environment, the effect of mirroring partnership state  changes, and the effect of mirroring failovers on replication. In addition, it describes  how to use LSN-based initialization to recover from the failover of a mirrored  subscriber database. Although brief overviews are given of both replication and database mirroring, it is  easier to understand this white paper if the reader has some experience with one or  both of these technologies, and has at least a rudimentary knowledge of database  concepts such as transactions.
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
SQL Server Replication: Providing High Availability using Database Mirroring 2 Introduction Transactional replication is the mechanism that Microsoft ®  SQL Server ®  provides to  publish incremental data and schema changes to subscribers. The changes are  published (the replication stream) in the order in which they occur, and typically  there is low latency between the time the change is made on the Publisher and the  time the change takes effect on the Subscriber. This enables a number of  scenarios, such as scaling out a query workload or propagating data from a central  office to remote offices and vice-versa. This form of replication always uses a  hierarchical hub and spoke topology. The addition of peer-to-peer transactional replication in SQL Server 2005 simplifies  the implementation of a bi-directional transactional replication topology, where the  replication stream flows both ways. In this topology, any participating node may read  or update the data. Properly partitioned modifications are propagated between all  nodes in a full mesh topology (as shown in Figure 1), allowing the data to be highly  available in the event that one server is unavailable. This feature has been further  improved in SQL Server 2008 with conflict detection and online changes for peer-to- peer topologies. Figure 1: Full mesh topology for peer-to-peer replication with three and four  nodes Transactional replication topologies can be made more resilient to server failures,  and hence more highly available, by adding redundant copies of the various  databases involved. This is especially important for hub and spoke topologies. Care  must be taken, however, because replication is reliant on the server names of the  servers in the topology, so any failover to another server can result in the replication  stream being broken.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern