Traditionally, IDS has provided multiple robust solutions forsupporting high availability data replication options. Previousreleases of IDS have supported two replication technologies: EnterpriseReplication (ER) and High Availability Data Replication (HDR). By usingthese technologies together, customers are able to achieve very highlevels of data availability. Both replication technologiescan be integrated with each other and coexist with other availabilitysolutions such as disk mirroring.
While HDR and ER have been features of IDS for many years, and haveproven to be highly reliable and low-maintenance technologies. IDS nowadds support for two new types of secondary servers:
- Secondary servers that share the same physical disk. TheShared Disk Secondary (SDS) servers provide increased availability byallowing one or more instances of the IDS server to attach to the samedisk subsystem, providing redundancy for the server in addition to dataredundancy solutions
- Additional remote secondary servers. The Remote StandaloneSecondary (RSS) servers extend HDR to provide multiple local or remotebackup servers that also replicate the data.
Both SDS and RSS servers provide customers a way to obtain increasedcapacity by distributing workload across multiple servers.Customers canchoose any of these solutions on their own. They become even morepowerful by combining all three types of topologies together. AddingEnterprise Replication, a completely customized availability solutioncan be delivered to meet each unique availability requirement.. Theseconfigurations are simple to set up and maintain, and are highlyscalable.
The following image depicts a Continuous Availability solution with 3tier protection. For example, if the Primary in Building-A inNew Orleans went down for some reason the role of the primary caneasily be switched to one of the SDS servers running on the bladeserver in Building-B. This would cause all other secondaryservers to automatically connect to the new primary server. If both the servers in New Orleans died, Memphisbecomes your Primary and Denver can be made HDR secondary and you mayeven add some SDS servers to Memphis blade server for load balance.
To learn more about this feature, please read the following white paperwritten by the architects of this feature:
Whitepaper on MACH11 technology.