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
