SMART: disk problems on RAIDZ1 pool: (ada6:ahcich6:0:0:0): CAM status: ATA Status Error

Freddie Cash fjwcash at
Tue Dec 12 23:26:10 UTC 2017

On Tue, Dec 12, 2017 at 2:55 PM, Rodney W. Grimes <
freebsd-rwg at> wrote:

> Hum, just noticed this.  25k hours power on, 2M load cycles, this is
> very hard on a hard drive.  Your drive is going into power save mode
> and unloading the heads.  Infact at a rate of 81 times per hour?
> Oh, I can not believe that.  Either way we need to get this stopped,
> it shall wear your drives out.

​Believe it.  :)  The WD Green drives have a head parking timeout of 15
seconds, and no way to disable that anymore.  You used to be able to boot
into DOS and run the tler.exe program from WD to disable the auto-parking
feature, but they removed that ability fairly quickly.

The Green drives are meant to be used in systems that spend most of their
time idle.  Trying to use them in an always-on RAID array is just asking
for trouble.  They are only warrantied for a couple hundred thousand head
parkings or something ridiculous like that.  2 million puts it way out of
the warranty coverage.  :(

We had 24 of them in a ZFS pool back when they were first released as they
were very inexpensive.  They lead to more downtime and replacement costs
than any other drive we've used since (or even before).  Just don't use
them in any kind of RAID array or always-on system.

Freddie Cash
fjwcash at

More information about the freebsd-current mailing list