In my previous posts I described how Oracle ASM can be used to build stretched clusters. I also pointed to some limitations of that scenario. But I am by far not the first one in doing so – and some…
Stretched clustering basics
Before showing my preferred solution for Oracle stretched high availability clusters, first some clustering basics. Active/passive versus Active/Active clusters Most clustering software is based on active/passive scenarios. You have a system (say, a database) that is running on a set…
Limitations of host-based mirroring for stretched clusters
For data mirroring, EMC SRDF is sometimes used in such a setup that both servers write to one location only (the “far” server writes across dark fibre links to the local storage). EMC has similar tools (Mirrorview, Recoverpoint, etc) for…
Extreme availability with Oracle stretched clusters
Some of my customers have been pushing for more availability in their Oracle database applications. They want to eliminate downtime completely even if they experience a site failure. Whether this is a real business requirement or a technology push, I’m…