[Zope] Fail-safe redundancy policies for Zope

What are the best, or most used fail-safe redundancy practices suitable to Zope? More in detail, I'm working on a Zope-based system that will store the data inside the ZODB, and one of the design requests is that given an unrecoverable hardware crash, the system could continue running using a mirror installation with the latest backup (not later than half an hour or even less.) APE looks like the way to go since it allows the use of standard backup software, but you may have tried other possible solutions for a problem like this. According to your experience how would you accomplish it? Thanks in advance, Ausum