On Thu, 12 Jun 2008, Kendall Shaw wrote:

> I suspect this is going to be a silly question. Since disk drives are
> cheaper than tapes, I think. Why do people use tapes rather than hotplug
> disks?

#1

Disks are complex mechanical devices and inherently fragile.

Tapes aren't.

 This is important if backups are going into a fire safe on an upper floor.
 One part of the specifiations for fire safes calls for a 7 metre drop
 when hot (simulating partial building collapse). Would a disk survive
 that?

 Apart from the above, disks are simply more susceptable to mechanical
 damage. If I drop a tape I can be reasonably sure it will be OK. If I do
 the same to a disk, even if it's ok now I'd replace it immediately
 because damage is cumulative.

#2

Tapes are generally warranted for XYZ period of data storage

Disks aren't.

#3

Higher capacity formats such as LTO3 or higher can stream at considerably
higher speed than disks == faster backups.

#4

In high capacity formats tapes are still cheaper.

#5

Disks still have a 1% or so DOA or early mortality rate.



Having said all that - for home use, I do use hotplug disks (and would
recommend this over DDS even in a SOHO or small business setup), but at
the scale I'm working with (80TB and growing all the time) I can't afford
the time to deal with faulty backup media.

Also of importance, Noone has yet tried to sell me a hotplug disk robot...


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