eXtremeDB High Availability, Fault-tolerant Database System
eXtremeDB High Availability (HA) database system is a fault-tolerant version of the already dependable eXtremeDB®. It was designed to answer the challenge, “How can a database survive the failure of the software or hardware environment in which it operates?” Designed to power systems that cannot afford to fail, eXtremeDB-HA delivers the highest degree of reliability, along with its unsurpassed performance and exceptionally small footprint. Process control, telecom and network gear, and other mission critical systems with demanding “five-nines” reliability (99.999% up-time). requirements comprise a fast-growing segment of real-time applications. These systems are managing greater volumes of more complex data—creating a need for a fast, lightweight commercial off-the-shelf (COTS) database that can meet their reliability imperative.
How does eXtremeDB HA work?
eXtremeDB-HA is an active-passive distributed database implementation. Active-passive means that there is one master database, and one or more slave (aka replica) database. The eXtremeDB-HA achieves high availability by maintaining identical database instances (two or more) through processes called synchronization and replication. Synchronization is the means of bringing a newly connected replica to an initially consistent state with the master. Replication is the means of maintaining master-slave consistency by replaying transactions from the master to the slave.
|Static synchronization||Fast||– Blocking|
|Hot synchronization||Not as fast||– Non-blocking|
|Asynchronous/Lazy/1-safe replication||Fast||– Small risk of dropped transactions on failover|
– Lower consistency
“Transaction Window” API can explicitly control the number of transactions at risk, and/or force synchronization of replica on demand
|Synchronous/Eager/2-safe replication||Not as fast||– Guaranteed consistency|
– No risk of dropped transactions on failover
Learn more about these other eXtremeDB-HA features:
It is important to note that eXtremeDB-HA replicates transactions, not individual insert/update/delete operations, and does so through real-time communication over TCP/IP, UPD/IP (with guaranteed delivery), Named Pipes and QNX Messaging.
eXtremeDB-HA replication through real-time communication assures the transactional integrity and consistency of databases, and nearly instantaneous failover if necessary. In contrast, other DBMS implement replication through log files, which results in higher latency and lower consistency.