An expert's recommendation for a SAN failover method
In a SAN, the term "failover
" is usually used to indicate a dual-attached host's access port failover to another HBA. Host port failover is accomplished with a "filter driver" located either in the OS (Like MPXIO in Solaris or MPIO in Windows) or via a driver provided by the storage vendor (Like Powerpath from EMC, Securepath from Compaq or HDLM from Hitachi).
In the case of your question, I take the term "failover" to mean application level failover to another location that would imply a form of data replication. There is no basic recommended solution, since the solution chosen would require an assessment of your environment. If you have the bandwidth between sites and your distance between sites is sort enough to keep latency low, then SYNC replication
would be the way to go. If there is a great distance between sites, then ASYNC
replication would be better. If you have limited bandwidth, then log shipping would be the next method I would choose.
Editor's note: Do you agree with this expert's response? If you have more to share, post it in one of our
This was first published in February 2004