[parisc-linux] palo II

[Stian Søiland]

On 2003-06-11 19:51:10, Matthew Wilcox wrote:

> On Wed, Jun 11, 2003 at 07:46:54PM +0200, Joel Soete wrote:
> > Anoyed to change my fstab because I add or remove a disk to/from the ex=
ternal
> > scsi controler of my b2k (boot disk sda became sdb, sdc, or what else),
> > I decide so to test devfs kernel. It seems to works (excepted that I co=
uld
> > not specify root=/dev/scsi/host1/bus0/target5/lun0/part5)
> (a) devfs is shit.  do not use it.
> (b) even if it's compiled in, the kernel still matches `root=' against a
> built-in table that has nothing to do with devfs.
> (c) devfs is shit.  do not use it.

This thread is going way off-topic for the parisc-list.. but.. I feel
the need to disagree anyway! =)

Your argumentation is flawed.

Joel gave a perfect example of when devfs would come of perfect use,
variation of scsi devices fucks up "sdb", "sdc" and so on. 

I earlier mentioned another fine use of devfs, to avoid the trouble of
constantly changing major number for /dev/ttB0 =)

Matthew, I wonder if it would not be possible to have a ext3-label
'root' on the partition and say root=LABEL=root (even though that would
look rather weird =) )

    tune2fs -L root /dev/bla/blah

LABEL=blapp can be used in fstab aswell.

Sad things I've discovered:

  * reiserfs does not support those labels
  
  * you cannot have two devices with the same labels
    (I tried to have multiple BOOT-partitions, with hopes that
    witchever was available could be used, however, that won't
    work when both devices are present, of course =) )
  
  * Labels DON'T work with software raid, because the kernel will
    recognize the labels even on the seperate units of the raid, 
    and start complaining about multible labels.
  
    However, you might specify raids using their UUIDs in 
    /etc/mdadm/mdadm.conf:
  
    # root
    ARRAY /dev/md/0 UUID=9ec52c6f:af4958dd:4c8ff16e:95abab7c spare-group=ekstra
    # usr
    ARRAY /dev/md/1 UUID=bd627bf7:8fcae3d0:4f3f4fe7:7b3786df spare-group=ekstra
    # home
    ARRAY /dev/md/2 UUID=47e9c924:5bbda641:b506006e:599c80e5 spare-group=ekstra
  
    ... but.. I've had trouble with usr and home switching place (md1 and
    md2) from now and then anyway, so maybe this is just a teoretical
    feature =)
  
    Obligatory quote from bash.org:

      #85899 +(53)- [X]
      * unchellmatt does the RAID lovers cheer... "ARRAY! ARRAY!"

I don't think you will be able to use devfs in root= as /dev can't be
mounted before / (unless you use initrd, that is, but I haven't figured
out how to do that with palo)

-- 
Stian Søiland               Work toward win-win situation. Win-lose
Trondheim, Norway           is where you win and the other lose.
http://www.soiland.no/      Lose-lose and lose-win are left as an
                            exercise to the reader.  [Limoncelli/Hogan]