MyBook World Edition Spindown

Short intro

While searching for information how to automatically spindown SATA devices without using ACPI, I have found the following post on some forum:

Years ago I had many serious problems because I wasn't disciplined about backing-up. I don't have the My book but I have used externals for many years and currently have 5 in a combination of WD, Maxtor and Seagate, and I will say without hesitation that external drives should be off when not in use. HD failure is not a question of if, but of when. There is no reason to have a drive spinning, burning life out of it, when you do not need it. None of my drives use a third party software utility, so I can't comment on that either, except that you must have some WD software loaded to trigger it. I'd be interested in someone's answer for this. Good luck.

When I bought my MyBook WE, first thing that came to my mind is if the drive supports automatic spin-down like other MyBooks. Maybe I did something wrong, but the drive never spinned down, even when disconnected from LAN.

So, I am going to write a tool that will monitor drive activity and automatically spin-down the drive when idle for a while.

I've got an e-mail from Joe Presson regarding this topic. He wrote:
I spoke with someone in the aerospace industry about the spin-down issue. He suggested there is a possibility it may not be a concern for the following reasons:

1. WD has marketed this as a Quiet'n'Cool device. And "reliably cool" (from wd website) implies a good lifetime at its operating temp. It also appears to be marketed as a 24/7 device.

2. The wear and tear on motors/bearings as a result of even a single stop/start may outweigh the impact of a "glide", even for several days. There should be literature about this, (check drive supplier websites?) and you can see whether it's worth the trouble. My guess is that mechanisms have gotten so good you'll decide not to worry. If the mfr is able to sell a 24/7 device with 24/7 reliability (i.e., endurance), I'd just smile and say "thanks."

I am not a hardware expert and can only speculate, but found the points interesting.

Well, my opinion is that it's worth it for three reasons:

Spinup Debugging

My disk spins up all the time and I have no clue what causes this. Can I debug this?

Yes, you can. But first, check that you have modified your syslog.conf to not sync, as described in the last question of the previous section. To debug disk activity, you can do:

echo 1 > /proc/sys/vm/block_dump

(Warning: you must disable syslogd before you do this, or you must make sure that kernel output is not logged. If you forget this, your system may get into a feedback loop, where syslogd causes disk activity, this causes kernel output, and this causes syslogd to do more disk activity, etcetera!)

This enables file/disk activity debugging in the kernel. You can read the output using dmesg. When you're done, disable block dump using

echo 0 > /proc/sys/vm/block_dump