Re: San-Based replication VS DataGuard replication
Date: Fri, 26 Sep 2008 22:40:14 -0700
> I have a database at Site1 stored on a SAN, and a disaster-recovery
> site2 with identical hardware. They are connected by high-speed fiber.
> (Both SANs are enterprise-class with full journaling capabilities in
> case the connection were ever severed.)
> I am researching Pros & Cons of using DataGuard to keep Site2 ready
> for disaster time, VS letting the SAN manage keeping the two sites in
> What are your opinions on these 2 methods?
> Thank you!!
There is a place in an Oracle shop for both SAN based replication and Data Guard but the SAN based replication will NEVER better Data Guard if the point is to have a DR site: Here are just a couple of the reasons.
- Data Guard checks what it replicates for internal logic. A SAN will happily replicate corrupt blocks.
- Data Guard can guarantee zero data loss even when the data has not been written to a data file. You can not make SAN replication synchronous.
- If SAN replication fails your primary will happily keep right on running transactions. Data Guard can be configured to bring things to a halt until the issue is resolved.
- Data Guard, interestingly enough, is more efficient. What is being replicated is the transactions themselves not operating system blocks so are shipping less data. -- Daniel A. Morgan Oracle Ace Director & Instructor University of Washington damorgan_at_x.washington.edu (replace x with u to respond) Puget Sound Oracle Users Group www.psoug.org