Re: Fixed (hardisk) device names?

["Jason Lim" <maillist@jasonlim.com>]

> > If i now must remove the first harddisk (/dev/hda) the second
(/dev/hdb)
> > will be renamed to (/dev/hda) after the reboot. As i want /dev/hdb to
be

> that's EXACTLY what linux does for IDE drives.  the slave drive on the
primary
> IDE controller will *always* be /dev/hdb, regardless of whether there is
a
> master drive or not.
>
> /dev/hda  - master drive on primary IDE controller
> /dev/hdb  - slave drive on primary IDE controller
> /dev/hdc  - master drive on secondary IDE controller
> /dev/hdd  - slave drive on secondary IDE controller
>
> > Is this possible?
>
> it's standard.
>

I think that is his point... but it doesn't do that for him. Apparently...
he has a master drive (hda) and slave drive (hdb) on the primary IDE
controller... but if he then removed the master drive, then suddenly the
slave drive becomes hda! Correct me if i'm wrong... :-)

Personally i've never seen that happen. The ONLY thing i could think of...
is to specifically set the jumpers on the HDs to FORCE one hard disk to be
master, and the other to be slave. That way, it is IMPOSSIBLE for the
system to get it wrong. Do not rely on the "cable select" jumper.

> don't use dd for that.  set up a raid-1 mirror instead.  it's easy to
do, only
> about 5 minutes work.

If only it was really so easy...

personally, i use 3ware cards... but just recently one of the 3ware cards
barfed, and turned a RAID 1 (with 2 HDs and 1 spare) somehow into a RAID 1
with 2 drives (the 1 HD and the spare) AND another RAID 1 with 1 drive
(which used to be part of the original RAID 1). Ever seen something like
this before?

I was looking at MONDO for a solution to this... but it does not appear
that MONDO will be able to resolve this very well at all and adds a whole
level of complexity to the setup. I was thinking... perhaps a solution
would be to setup a RAID 1 between the 3ware RAID 1 and a large IDE HD.
Would that be a good workaround in case of catastrophic failure on the
3ware RAID?


> also, for performance and safety, put your second drive on a separate
IDE
> controller.  that way it will still work even if one IDE controller
fails.
> e.g. have /dev/hda (primary IDE master) and /dev/hdc (secondary IDE
master)
> rather than /dev/hda & /dev/hdb.

That is always a good suggestion. Even if the cable had a problem both
drives won't be affected... the only cost to do this is that of an extra
IDE cable, so no reason not to!