Re: [TUHS] Is it time to resurrect the original dsw (delete with switches)?

[Jon Steinhart <jon@fourwinds.com>]

Hey, wanted to thank everybody for the good information on this topic.
Was pleasantly surprised that we got through it without a flame war :-)

I have a related question in case any of you have actual factual knowledge
of disk drive internals.  A friend who used to be in charge of reliability
engineering at Seagate used to be a great resource but he's now retired.
For example, years ago someone ranted at me about disk manufacturers
sacrificing reliability to save a few pennies by removing the head ramp;
I asked my friend who explained to me how that ramp was removed to improve
reliability.

So my personal setup here bucks conventional wisdom in that I don't do RAID.
One reason is that I read the Google reliability studies years ago and
interpreted them to say that if I bought a stack of disks on the same day I
could expect them to fail at about the same time.  Another reason is that
24x7 spinning disk drives is the biggest power consumer in my office.  Last
reason is that my big drives hold media (music/photos/video), so if one dies
it's not going to be any sort of critical interruption.

My strategy is to keep three (+) copies.  I realized that I first came across
this wisdom while learning both code and spelunking as a teenager from Carl
Christensen and Heinz Lycklama in the guise of how many spare headlamps one
should have when spelunking.  There's the copy on my main machine, another in
a fire safe, and I rsync to another copy on a duplicate machine up at my ski
condo.  Plus, I keep lots of old fragments of stuff on retired small (<10T)
disks that are left over from past systems.  And, a lot of the music part of
my collection is backed up by proof-of-purchase CDs in the store room or
shared with many others so it's not too hard to recover.

Long intro, on to the question.  Anyone know what it does to reliability to
spin disks up and down.  I don't really need the media disks to be constantly
spinning; when whatever I'm listening to in the evening finishes the disk
could spin down until morning to save energy.  Likewise the video disk drive
is at most used for a few hours a day.

My big disks (currently 16T and 12T) bake when they're spinning which can't
be great for them, but I don't know how that compares to mechanical stress
from spinning up and down from a reliability standpoint.  Anyone know?

Jon