dk wedges, or shooting oneself in the foot for profit and pleasure...

[Chavdar Ivanov <ci4ic4%gmail.com@localhost>]

Hi,

I had to replace an old and finally failed IBM Deathstar disk on one
of my -current systems; there was this 120GB PATA disk lying around,
looking too large for what was in use before, so I decided to make use
of the versatility of GPT and wedges - which I had never come to try
before - to split it in few slices with different usage and also iSCSI
targets. Got my kernel (5.99.21 from yesterday) compiled with the all
the DK* parameters turned on, booted single user, tweaked /etc/fstab
and all was well. The problem was, my root disk is a reasonably fast
SCSI 10K 18G one, three PATA disks are used for various slices (to
include the new 120GB, so far unused). The SCSI disk gets its wedges
auto-discovered last, so whenever I add a new one to the large disk I
have to edit the fstab file. OK, that is in the GENERIC comments, so
one is warned, of course. The trouble came when I made a wedge to use
as an iSCSI target; it worked just fine, I unfortunately edited
/etc/iscsi/targets specifying it and even started doing some data
moving from a Vista initiator to get a feeling for the speed to
expect. As I was about to leave the office, I decided to reboot and
correct the fstab file with the new value of the root wedge, and so I
did, forgetting to edit the targets file or to disable iscsi_target.
The new root wedge name turned to be exactly the wedge which was
created previously for the iscsi target... so my root slice was
promptly offered as a target by the iSCSI initiator, the initiator
still moving the data about... The end result is, fsck on the root
wedge panics (I don't think the trace is useful, considering the
obvious damage), so I will have to reinstall again (no big deal, as I
did that a few weeks ago for different reasons, the data and the
pkgsrc packages are intact).

OK, we all know the ways users manage to shoot themselves in the feet
are countless.

The question: is there a way to force the wedge discovery to go in a
predefined way to avoid the change of the root wedge every time, in my
case to force the SCSI disk to be first in the queue?
-- 
Chavdar Ivanov
----
Ted Turner  - "Sports is like a war without the killing." -
http://www.brainyquote.com/quotes/authors/t/ted_turner.html