I appreciate the thoughtful discussion of this topic.

>The way I figure, in order, the most important factors regarding 
>the tape backup system are:
>1. Reliability
>2. Performance
>3. Ease
>4. Cost

What about capacity?

That said, I think such a listing oversimplifies the equation. What if 
Sony came out with an incredibly reliable backup systems using RAID 5 and 
three IBM 75 GB hard drives. Reliability, performance, and ease would be 
out of this world -- but cost would be prohibitive, as you'd have to buy 
a new RAID array every time you filled up the 150 GB storage space. Thus, 
cost is not at the bottom of the pile.

This may sound a bit philosophical, but a simple ranking of factors does 
an injustice to the complexities of the decision making process.

1. Reliability. Nobody wants an unreliable backup mechanism. Nobody will 
last long in the business selling one. We can rule out unreliable drives, 
so this is a binary decision.

2. I'm assuming you mean throughput here. Beyond a certain point, 
somewhere around 60-70 MB/min., you saturate 10Base-T. I don't know of 
any backup system that can saturate 100Base-T, let alone Gigabit 
ethernet. The key here isn't necessarily the fastest mechanism, but a 
fast enough one for today and the next 2-3 years. That said, for some 
users USB is adequate.

3. Ease is ambiguous. For me, ease would encompass how many tapes or 
disks constitute a backup set. At home, I'd like to stick with one (VXA 
gave me 19 GB on my first backup tape; that lasted well over a month). At 
work, that's just not feasible. We're using AIT and filling 4 25 GB tapes 
(33 GB compressed) per month.

4. Cost is also ambiguous. There is the cost of the mechanism, the cost 
of the tape, the cost of the backup set, the cost of storage. Based on 
your own backup needs, I suggest you plot out the costs for one, two, and 
three years of use. (You might even want two drives or a loader to keep 
backup going when the first tape fills.) This got us to AIT at work and 
helped me pick VXA at home.

Other than reliability, we have to weight these according to our needs. I 
don't want to have a pile of Zip disks or backup tapes at home. At work, 
that's not really an option.

In the end, we weigh throughput, capacity, and cost, then make what feels 
like the best choice based on our biases. As some have noted, those 
biases are very different in the home compared with the workplace.

Dan Knight, information systems manager       [EMAIL PROTECTED]
Baker Book House Company                 <http://www.bakerbooks.com>
6030 East Fulton                                   616-676-9185 x146
Ada, Michigan 49301                                 fax 616-676-9573

 - Macintosh: Love bug resistant, always Y2K ready

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