RAID1 and RAID5 (as well as RAID10, RAID15, etc.) are great ways at having the "live" data ready for failures. RAID stands for "redundant array of inexpensive disks" and is actually not a "backup" method. Backups are ways to store the data and take them offline so they are not "live" and once created are independent of the original "live" data. This is why tapes, CD's, DVD's, external hard drives, etc. are used for offline "backups". Depending on the funds, the computer hardware, network layout, what you consider "important data", etc. all changes the way you would backup Microvellum or actually anything. IMHO, the best choice is a mixture of these technologies that will not break the companies budget.
RAID1 by itself is not enough to make me feel comfortable about the data. For that matter, neither is RAID5. I would want a RAID level of some sort (mirror or striping with parity or both) PLUS a tape backup and/or multiple DVD backups, and/or an external USB hard drive, and (if budget allows) offsite data storage.
Ultimately, I would want to have as many redundant options as possible in case the data really does need to be restored because when restoring data it is usually found out then that the backups didn't quite work right (or so-and-so left the DVD/tape/hard drive in their car and it got too hot/spilled coke on it/...).
Which brings me to another point... the only *real* way to test a backup is to restore it in its entirity. For many companies this is hard to do because it either requires planned downtime to "break" the server and restore the data, OR another server that is used only when data needs to be restored. Both of these options are usually too expensive and/or time consuming (money as well) for small business to handle.
Backing up and restoring (especially restoring) is a headache. Hard drive images/snapshots are another option and are helpful but take a lot of space usually. Software like Acronis True Image will do things like this (so will the UNIX command "dd" piped into gzip).
Good luck 