Re: iPod authorization

G.T. <getnews1@xxxxxxxxxxxxxx> wrote:

> Because filesystems and RAID do fail.

Been there. Done that. *EVERYTHING* fails. A strategy based on "this
setup can't fail" is based on a false premise, no matter what the setup
is - even one that includes multiple off-site backups. WWIII would
probably take them all out; whether you would still care is another
question. All such things are more properly a matter of cost/benefit
tradeoffs more along the line of "the odds of this failing are low
enough that the costs of doing better aren't worth the return." Now that
tradeoff might well give the answer that Dave's approach is fine for his
needs - in fact, I'd suspect that it is so, so this isn't meant as a
criticism of Dave's choice.

RAIDs protect against only a few specific kinds of failures. They are
quite vulnerable to several other "common mode failures". Ones I have
personally seen include:

1. Yes, the system was on an UPS, but the UPS failed in a way that put
through a huge power spike and took out multiple drives. :-(

2. Fire in the computer room. Yep, that one caused a building evacuation
at work, and I still recall the white face on the hardware maintenance
guy when he looked up and saw the smoke comming from the computer room
window and realized that, not only was this not a drill or false alarm,
but that it was his computer burning. :-(

3. And then, of course, there all the classic cases of human error. If
some human accidentally goes in and deletes everything, overriding all
the security settings, and thinking he is doing something else, that
RAID system will "nicely" propogate his mistake to as many copies as it
maintains. I've seen variants of that one multiple times. :-(

A bit of a pet peeve of mine... as I've listened to vendors try to sell
their systems based on a claim that they "can't fail" and thus don't
need backups... while then describing an architecture that would have
failed under scenarios I've actually seen for the system they were
trying to replace. I've not tended to be very receptive to those sales
pitches for some reason. This is for some high-value data at work - data
that cost literally hundreds of millions of dollars to acquire, so we
are actually a bit picky about it. Not quite the same situation as my
music collection.

--
Richard Maine | Good judgment comes from experience;
email: my first.last at org.domain| experience comes from bad judgment.
org: nasa, domain: gov | -- Mark Twain
.

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