Now keeping in mind that I've never realy done any serious administration, I think I prefer optical media for backups, unless you have a whole mess of information to backup.
There are a few reasons for this. The first one is that the cost of tapes and the tape drive is very high compared to dvd disks. Compare the cost of a 3-4 high-quality dvd drives with a few hundred dvd blanks vs a full fledged tape drive + tapes.
dvds are basicly disposable after your finished using them... you can end up doing things like being able to make full backups a few times a week with a 'archival' backup every weekend that you save, and then store that in a secure storage place. That way you can end up with full backups that are saved going back thru the company's history that will contain multiple revisions of files and such. Say if you got hacked and you didn't realise it for a month you don't want all your aviable backups to be only aviable from the machine during the time it was root'd.
Say if you ended up 'archiving' 2 double-sided dvds a week. Well then the entire years worth of backups can be kept in a object about the size of a shoebox... That's about a 104 dvds. So the storage costs are relatively low. Of course if the amount of data you require to save is about a hundred dvds a week, then obviously that's becoming silly.
Another advantage with DVDs are is that it's a ubiquitous media. Almost any semi-modern computer will be able read the disks. Even if you choose a dvd version that's fairly exotic, like double-sided, or DVD-ram, you can be reasonably sure that you can run down to the store and get a device that will read them properly.
With a tape drive, they are much more rare. Say you have a fire in the computer room/closet and the tape drive is obiterated, or a electrical surge takes it out.. or it just fails. How long/difficult/expensive is it going to cost to find a replacement to read the backups? So in your off-site storage will you have to store a second tape drive there too, or maybe you'd have to have a support contract to make sure that one is aviable the day you need it. But it's hard to beat being able to run down to Compusa and get a new drive in under 20 minutes, or being able to read the backup onto your latpop or whatnot.
Then since the price overhead is low it would be easy to upgrade to newer DVD technologies over time and if you pay attention to at least read backward compatability then as your storage needs increase so can the capacity of the drives. With tapes since you have a higher investment in the media and drives and backward compatability issues and such it makes it more difficult.
However on the other hand.. Tapes are much more convienient and are probably much more relaible in terms of actual media you end up with. You don't have to worry so much about bad burns.. for instance if the DMA access gets turned off for the dvd drive by some freakish bios thing, then if you don't test your media with optical you could end up with all your backups being full of errors and bad burns.
If you have a couple terrabytes worth of data you need to keep safe then probably optical is silly.
Also they are probably easier to do more constant backups.
It all depends on the volume of material you have to keep safe and the frequency of backups.
And the difficulty of managing the backups is very important, too. Since there would be no onsite administrator your going to have to depend on a secretary or owner or somebody like that to manage the backups.
If it's too expensive, complex, or annoying then that dramaticly increases the likelyhood that it won't be done, or that it won't be done properly. Most lay-people don't understand the importance of backups and after months and maybe years of 'everything just works' it's highly likely that they won't get done properly and they'll lapse into bad habits.
The most reliable and very superior way of doing backups is full backups every evening, and then a offsite storage for some of those. But that's expensive and irritating.
It's popular to do incremental backups, which I don't like as much, but it's still usefull...
The thing is is how much time can the business afford to loose? Everybody has different needs and such.
If it's just for a static website or a website that shows off the company catalog or something then it maybe fairly safe to only do a backup of it every month or so. Then again if it's a small business and they set it up so that contractors place order for thousands of dollars worth of material thru the website daily then loosing a couple days of data would be devastating.
If you do incremental backups to a second computer with disks, then do real backups on secure media every weekend.. then how is it going to work out if there is a electrical storm and all your computers are fried friday evening before backups are done... Will the company be able to handle having a weeks worth of data erased?
A lot of places would be able to handle that. A lot of places wouldn't. Keep in mind that most companies are increasing dependant on computer systems and that MOST companies that suffer massive data corruption/loss DO go out of business. It's a fact.
Now this is just a LAMP server, so it's probably non critical. I don't know what they are using it for or anything like that.
But there are nice ways to do it, for example:
Say you get the server setup, total size of the DB + software isn't going to be more then 6 gigs. It's a 5 day a week 7:30-7:30 workday enviroment.
In the boss's secretaries computer you stick in a couple very nice dvd drives and make sure the machine is plenty fast to handle the information and you setup a nice automated thing. Every monday, wensday, and friday night before leaving work she pops in a couple dvd disks. It sends a email to her, her boss, and you on the status of the backups (successfull, fail, no disks, etc). Once a month or so the backups get tested/looked at to make sure that everything is still working. Monday morning she takes the friday's dvds and sticks them in nice jeweled cases with a nice printed out lables and she sticks them in a UPS envelope and mails them to the off-site storage place.
So that way you end up with 3 full backups a week. If a electrical storm happens over night and takes out the computer closet, then the backups are hopefully done and in a different room. If the boss did it then he may get lazy and blow it off, with the secretary doing it with easy to read notifications to interested parties then it's more likely to get done. And then offsite storage is taken care off.
Even if the entire building was destroyed in a tornado or whatnot then the most possible they could loose would be a weeks worth of data. The offsite storage could even be in a different geographical region without increasing costs by much.
So that's one idea.
Were I work we only do backups on the weekend, they go to tape, and they sent to offsite storage. On the monday the delivery guy comes back drops off last week's backup and picks up the new stuff. It's my job, and two other people's, to make sure that they run and all that.
so those are my thoughts on the subject.
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