Re: hd numbering in 9.0beta1

2011-08-29 Thread Andriy Gapon 
on 29/08/2011 10:10 Roger Genre said the following:
 Perhaps I miss some important new feature introduced in 9.0 to work around 
 that
 problem ?

Most likely you just overlook a CAM feature that you have not needed before.
Please see cam(4), search for 'wired'.

-- 
Andriy Gapon
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Re: hd numbering in 9.0beta1

2011-08-29 Thread Garrett Cooper 

On Mon, 29 Aug 2011, Roger Genre wrote:


Hi everybody,

I would point out a problem related with the new way, coming in 9.0, to hard 
disks numbering.


As far I remember (5.0 ?), hardware detection  of H.D.'s at O.S. boot-up 
numbered every channel potentially able to attach a disk to, and tagged the 
disks really attached with the number of his control channel; the sequence 
(from lowers to highers numbers) begins with scsi or scsi-like (e-sata, usb, 
fire-wire,...) controllers and ends with the controllers directly depending 
from the chipset (sata at this time).


Such strategy allows to attach easily a new mass-storage device without 
modifying the disks numbering and thus the relevant fstab files.


9.0beta1 use a different numbering strategy,(with a similar sequence in 
harware detection) tagging succesively detected disks with adjacent numbers.


The best way I can put it has already been noted in the archives several 
months back:


- http://lists.freebsd.org/pipermail/freebsd-current/2011-April/024110.html
- http://lists.freebsd.org/pipermail/freebsd-current/2011-May/024495.html
- http://lists.freebsd.org/pipermail/freebsd-current/2011-April/024233.html

I don't have the corresponding commits right now, but I could dig them up 
as they spawned a large discussion thread as well.


The basic gist is that several folks agreed that:

1. GEOM/UFS labels were the only way to go.
2. There are some caveats to using GEOM labels that discourages use as a
   means of deterministically determining mountpoints.
3. A compatibility shim was added for ata - atacam transitioning; see
   kern.cam.ada.legacy_aliases in /sys/cam/ata/ata_da.c

Cheers,
-Garrett
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Re: hd numbering in 9.0beta1

2011-08-29 Thread Edho P Arief 
On Mon, Aug 29, 2011 at 2:10 PM, Roger Genre genre.ro...@orange.fr wrote:
 But adding a new hard disk will shift one, more, or all the previous
 numbers, (depênding from the channel the new disk is attached to), making
 the /etc/fstab files irrelevant, and leading kernel in panic at boot-up.


there's a good reason we have geom_label now.

My fstab now looks like this:

/dev/ufs/root3 / ufs rw,noatime 1 1
/dev/label/swap3 none swap sw 0 0
proc /proc procfs rw 0 0

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