>Yes mapprivate is available in the 5.3.4 release. One caveat, it only
>works when RVM is stored in a file.

That is good.  One note here, NetBSD (and I assume FreeBSD) will allow
you to private map a block device, so one doesn't have to use a file
in a FFS filesystem.  NetBSD won't let you private map a raw device,
but that should not be a problem.

>From what I understand, Linux won't let you private map a block
device, although I haven't tried it.

-- 
Phil Nelson                    NetBSD: http://www.netbsd.org
e-mail: phil@cs.wwu.edu        Coda: http://www.coda.cs.cmu.edu
http://www.cs.wwu.edu/~phil