Local High Availability and Remote Disaster Recovery (LHA/RDR)
Local High Availability and Remote Disaster Recovery (LHA/RDR) is a hybrid High Availability and Disaster
Recovery solution that combines the benefits of having a local high availability clustering solution with those of having a remote disaster recovery solution.
Clustering for high availability solutions like Microsoft Clustering Services (MSCS) significantly reduces
system down time caused by both unplanned and planned hardware and software failures. DB2 HADR is an
integrated feature that provides for both high availability and disaster recovery by replicating data from a
primary database to a standby database. HADR provides data protection for both partial system failures due
to hardware or software failures and complete site failures due to natural disasters.
There are of course advantages and disadvantages in both MSCS and HADR solutions. For example, MSCS
automates the fail over of software and hardware resources but is limited in it’s ability to fail over some
resources like shared storage over long distances. On the one hand HADR solves this limitation by as it
only requires a network connection from the primary database server to the standby database server allowing
the standby database server to be a true remote disaster (site loss) recovery solution, but on the other hand
HADR does not automate the fail over of hardware and software resources from the primary database server to the standby database server.
Combining clustering for high availability cluster solutions like Microsoft Clustering Services (MSCS) and
DB2 High Availability Disaster Recovery (HADR) into a hybrid solution solves this problem as well as other limitations typically imposed by remote disaster recovery sites.