Striped Drive for OS File System

[Donald E. Holt]

I haven't seen this particular situation discussed, nor have I been able
to find any specific information on the web. I am not experienced in
GEOM or vinum, so I may be asking a dumb question. If so, I apologize.

My system has FreeBSD installed across 2 SCSI drives. /dev/da2
holds /, /tmp, /var, and a swap. /dev/da4 is devoted to /usr and another
swap. A third drive (dev/da5) is dedicated to a Win4BSD virtual machine,
and is mounted as /WinXP (there are still a few MS apps I can't get
around using).

I'd like to expand /usr fs to an additional SCSI drive (physically
present now, but unused). Would it be possible to do that, perhaps with
gstripe, without distroying data on the current drive?

Again, sorry if I've asked one of those eye-rolling, forehead-thumping
questions.

Thanks!