but the marketing brief seems to suggest that if you lose a drive you
only lose the files that were on there.
with lvm you would lose any lv that has blocks on that drive
Not sure what Windows really guarantees in this regard, but yes, losing
a drive that is part of a larger volume is a problem. In many/most
cases you can actually recover all the files that are still on the
remaining drives, but it might take a bit of work (typically, you have
to tell LVM to use something similar to /dev/zero as a replacement for
you failed drive, and then you run `fsck' on your filesystem(s) which
will give you tons of errors and will recover most of the files (plus
others which actually aren't correct but where the missing bits have
silently been replaced by zeroes)).
As a general rule, you're better off relying on backups or RAID to
handle such situations anyway. Or seen from another point of view: if
it's OK with you to lose an arbitrarily chosen 1/3 or 1/2 of your data,
then why would you mind losing it all instead?