from Izumi Tsutsui:

> > > The problem here doesn't happen once after disabling NCQ by
> > > "hw.wd2.use_ncq=0" in /etc/sysctl.conf.

> > Excerpt from Simon Burge:

> > > For now, I'm running with this in /etc/rc.d/sysctl0 (should be run
> > > before fsck of /):

> > Maybe this sysctl has to be in place from the outset, before user gets to 
> > the login prompt?

> sysctl.conf(5) is handled by /etc/rc.d/sysctl, after
> /etc/rc.d/fsck is done.  If the SSD firmware NCQ bugs are
> triggered during fsck(8), sysctl.conf setting doesn't help.
> That's all.

> > So I appended to /etc/sysctl.conf for NetBSD 8.99.51 amd64 and i386
> > hw.wd1.use_ncq=0
> > and rebooted to make the change take effect.

> > Even so, it can take many hours to several days for the hard drive
> > crash to occur, so it is too early to see if this will work on a
> > Western Digital Green hard drive.

> I'm not sure if there is any evidence that says certain WD drives
> have bugs around NCQ functions.

Maybe Simon Burge's details are inaccurately stated?  I don't know but tried it 
anyway.

Some things have to be done by the init system to take effect.  This is true in 
Unix and quasi-Unix, DOS (C:\CONFIG.SYS), OS/2 and successors (C:\CONFIG.SYS), 
and I would guess MS-Windows as well.

The idea that preventing the hard drive crash by putting "hw.wd1.use_ncq=0" in 
/etc/sysctl.conf is, for my situation, hypothesis and not confirmed.

I had the notion that the hard drive crash would not happen when at a root 
console, but that proved wrong, the crash occurred, but took some days. 

My experience with WD Green hard drives is sufficiently unfavorable that I 
wouldn't want to buy such a hard drive ever again, and I guess enough other 
customers' experience was enough to prompt WD to discontinue the Green line.

Tom

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