Subject: Re: wedges and hotplugging
To: Jonathan A. Kollasch <>
From: Blair Sadewitz <>
List: current-users
Date: 11/14/2006 21:17:12
Yes, that is the problem; those sd devices are probed before some or
all (cannot remember, and on my machine dmesg is always corrupted) of
the wd devices.  I will have to figure out how to have those probed
last.  Time to look at the configuration ...



On 11/14/06, Jonathan A. Kollasch <> wrote:
> On Tue, Nov 14, 2006 at 05:16:52PM -0500, Blair Sadewitz wrote:
> > This will not help in my case--at least I don't think--because sd4
> > only appears if the flash drive is plugged into the USB port.  If it's
> > not, there is no device to pin down.  If the device is plugged in, a
> Oh, but it is.  That pinned down device is reserved just for what
> it matches.
> > wedge (dk device) is configured for it.  My flash card reader gets
> > probed as sd0-sd3, so if I insert cards in there, those get wedges,
> > too.  All of this autoconfiguration messes up the wedge assigments to
> > my fixed disks, which borks their assignment in fstab; and then I
> > can't boot to multiuser mode!
> You need to pin down those essential drives.  Unless the wedge code
> runs in undefined order, this should allow for predictable results.
> >
> > IMHO, this is significant concern re: the wedge implementation, unless
> > in the future things will be done differently. If there's something
> > I'm missing here, I request enlightenment/admonition.
> On one of my machines where I need this, I have virtually
> all possible drives pinned into place.  Again, assuming
> the wedge discovery code scans disks in order, this will
> allow for repeatable scan results.
> Of course, wedges will be created in the order the drives
> are scanned, this would be problematic if sd(4)s are scanned
> before wd(4)s.  Perhaps some config(8) machinery is needed
> to allow for groups of dk(4)s to be allocated to specific disks.
> 	Jonathan Kollasch

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