Strange HD-device

Christian Baer christian.baer at informatik.uni-dortmund.de
Sat Jan 28 05:53:35 PST 2006


Hello *!

I am experiencing a very annoying problem when trying to (re-) install
hard drives.

What happened is this:
I set up a new (private) server, removed all the hard drives from the
old one and installed these drives and one new drive in the new server.
The old server was running 4.11-STABLE, I installed 6.0-RELEASE on the
new one and kept it up to date with cvsup. That was the easy part.

Since the default file system in 6 is UFS2 and I wanted to encrypt a few
of the file systems with gbde(8), I decided to empty one drive after the
other, create new slices, partitions and file systems on the drives,
copy the data back on the drives and - while I'm at it - clean up the
data itself. :-)

When I installed new drives (ad0, which is the boot drive and ad8 which
is the new one), I created a new slice (dd-mode[1]) and new partition(s)
without any problems. I did notice that the letter for a single
partition changed from 'e' to 'd'. So a drive containing only a single
file system now is /dev/adxs1d[2].

The problems began whith a 160GB Samsung drive (SP1614N). I copied the
files off the drive and tested a few of them - just to be sure. Then I
decided to erase the drive completely, as it was destined to be
encrypted and I didn't want any unencrypted data left on it. So I
unmounted the file systen and did did a

  dd if=/dev/urandom of=/dev/ad6 bs=1024K

After that I started sysinstall and created a new slice and a new
partition which sysinstall called /dev/ad6s1d - which I expected. But
after creating the partition, the mount failed, because "no such file or
directory". And sure enough, ad6s1d did not exist in dev:

  jon# ls -l /dev/ad6*
  crw-r-----  1 root  operator    0,  76 Jan 22 15:23 /dev/ad6
  crw-r-----  1 root  operator    0,  93 Jan 22 15:00 /dev/ad6c
  crw-r-----  1 root  operator    0,  96 Jan 22 15:00 /dev/ad6cs1
  crw-r-----  1 root  operator    0,  92 Jan 22 15:00 /dev/ad6s1
  crw-r-----  1 root  operator    0,  94 Jan 22 15:00 /dev/ad6s1c

These devices look a bit like those of a drive with a "true"
partition-table (so Wintendo can read it). I can't really check that now
because I have no computer with such an installation. However, even if
this were so, I have checked and rechecked, the drive is definately
dangerously dedicated - or at least, it should be. Non of the other
drives show these devices:

  crw-r-----  1 root  operator    0,  73 Jan 22 16:20 /dev/ad0
  crw-r-----  1 root  operator    0,  79 Jan 22 16:20 /dev/ad0s1
  crw-r-----  1 root  operator    0, 100 Jan 22 16:20 /dev/ad0s1a
  crw-r-----  1 root  operator    0, 101 Jan 22 16:20 /dev/ad0s1b
  crw-r-----  1 root  operator    0, 102 Jan 22 16:20 /dev/ad0s1c
  crw-r-----  1 root  operator    0, 103 Jan 22 16:20 /dev/ad0s1d
  crw-r-----  1 root  operator    0, 104 Jan 22 16:20 /dev/ad0s1e
  crw-r-----  1 root  operator    0, 105 Jan 22 16:20 /dev/ad0s1f
  crw-r-----  1 root  operator    0, 106 Jan 22 16:20 /dev/ad0s1g
  crw-r-----  1 root  operator    0,  78 Jan 22 16:20 /dev/ad12
  crw-r-----  1 root  operator    0,  97 Jan 22 16:20 /dev/ad12s1
  crw-r-----  1 root  operator    0, 121 Jan 22 16:20 /dev/ad12s1c
  crw-r-----  1 root  operator    0, 122 Jan 22 16:20 /dev/ad12s1e
  crw-r-----  1 root  operator    0,  74 Jan 22 16:20 /dev/ad2
  crw-r-----  1 root  operator    0,  87 Jan 22 16:20 /dev/ad2s1
  crw-r-----  1 root  operator    0, 109 Jan 22 16:20 /dev/ad2s1c
  crw-r-----  1 root  operator    0, 110 Jan 22 16:20 /dev/ad2s1e
  crw-r-----  1 root  operator    0,  75 Jan 22 16:20 /dev/ad4
  crw-r-----  1 root  operator    0,  90 Jan 22 16:20 /dev/ad4s1
  crw-r-----  1 root  operator    0, 113 Jan 22 16:20 /dev/ad4s1c
  crw-r-----  1 root  operator    0, 114 Jan 22 16:20 /dev/ad4s1d
  crw-r-----  1 root  operator    0,  77 Jan 22 16:20 /dev/ad8
  crw-r-----  1 root  operator    0,  94 Jan 22 16:20 /dev/ad8s1
  crw-r-----  1 root  operator    0, 117 Jan 22 16:20 /dev/ad8s1c
  crw-r-----  1 root  operator    0, 118 Jan 22 16:20 /dev/ad8s1d

The drives ad2 and ad12 are still unchanged from the last installation
and therefore are still USF1 formatted.

There were three changes since I installed the UFs2-drives:

- I did a cvsup and made a new world.
- ACPI didn't seem to work to well with this mainboard[3], so I
  deactivated
  it in the board's BIOS. This led to a few error-messages during
  booting but that seems to be more of a "cosmetic" problem. I don't
  really believe this is the cause though, because I turned ACPI back on
  and got the same results.
- I added 'options GEOM_BDE' to the kernel config

Also there are two additional ATA-controllers in the computer. Both are
Promise: PDC20268 (for ad4 and ad6) and PDC20775 (for ad8 and ad12). The
other two drives are connected to the southbridge.

My basic question now is:
Where did I mess up? :-) Is it normal for the devices to have different
names?

Regards,
Chris

[1] Since only FreeBSD will ever touch this computer, all the drives are
    dd-mode
[2] Is there some text out there explaining these last letters? What are
    the first three letters (a-c) reserved for (now)? Somehow the
    handbood contradicts the results I get here.
[3] The computer would hang up during a shutdown. The last message
    always was "shutting down ACPI" and hence had to be rebooted via a
    hard-reset, which is a bit of a pain since the computer is nowhere
    near anything you could call "workspace".



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