gmirror on disks of different size

[Steven Schoch]

Pawel Jakub Dawidek wrote:

> AFAIK gvinum is supported.

In a previous message, Fred R. said that with 6.0, after running
gvinum start, the entries /dev/gvinum/* were not there.  Lukas Ertl
replied that gvinum was last supported in the latest -STABLE release,
which was not 6.0.  I also found that I couldn't use gvinum after
upgrading to 6.0, so I figured gvinum was not supported, or at least
on the back burner.

> With gmirror you can mirror any GEOM providers (disks, slices,
> partitions, stripes, encrypted providers - anything).

Thanks!  Alec Berryman also pointed me to
http://people.freebsd.org/~rse/mirror/ , which suggests using gmirror
on a slice, and then partitioning the gmirrored slice.

In order to avoid mirroring the swap partition, which seems unwise to
me, I'm planning on dividing each disk into two slices, with slice 2
taking up the last part of the disk.  Then I can gmirror as follows:

	# gmirror label root da0s1a da1s1a
	# gmirror label gm0 da0s2 da1s2

Then I'll use disklabel on gm0 to set up two partitions,
/dev/gmirror/gm0d for /usr and /dev/gmirror/gm0e for /var.  Then, I'll
have two swap partitions, da0s1b and da1s1b, and scratch partitions on
da1s1{d,e} (the larger disk).

Is there something wrong with doing it this way?  Is there a better way?