As most of us know that has worked with Domino server that are setup for using transaction logging, these servers are very sensitive to (even the smallest) issues with the drive (or filesystem) where the transaction logs are placed.
I sometimes work with IBM DB2 servers and they support setting up both primary and secondary log paths for transaction logging.
IBM DB2 also support setting up Overflow log paths and Mirror log paths.
The overflow log path would be of benefit when using Archived logging and if for some reason the backup of the transaction logs, doesn't run as smoothly as it should. We all know what happens when the log drive runs full!
Mirror log path would as well as providing increased stability also potentialy give a performance gain on servers with a high transaction rate.
Think one or more of these options are getting more and more important as Domino databases can get up 256 GB in size. And who knows, maybe even bigger in the foreseeable future.