RAID migration

[Jeremy Chadwick]

On Sun, Oct 12, 2008 at 10:27:47PM -0600, Anthony Chavez wrote:
> Jeremy Chadwick wrote:
> > On Sun, Oct 12, 2008 at 07:10:31PM -0600, Anthony Chavez wrote:
> >> Dear freebsd-questions,
> >>
> >> I have a HighPoint 1820 RAID controller that is using 1 channel for an
> >> OS drive and 3 channels for a RAID-5 array.  I'm interested in migrating
> >> to a new (possibly non-HighPoint) card, and am wondering if I will be
> >> able to plug the OS drive into one channel on the new card and have it
> >> "just work."  Is it a safe bet that it will?
> > 
> > It "probably" will work, assuming that the OS disk is not configured
> > as a RAID or array member in the RAID cards' BIOS.  Meaning, if you're
> > using the disk on the controller purely in a "JBOD" fashion, yes, it
> > should work.
> 
> In the WebGUI's "logical device information" section, that particular
> drive is listed as a "hard disk" whereas the other 3 are clearly spelled
> out as a "RAID 5" array.  When I shut the machine down, I will check the
> BIOS itself to see if it specifically states "JBOD."  Thanks for the
> pointer.

It probably won't.  JBOD is just a term used to describe a hard disk
hooked to a RAID controller but not part of a RAID array.

I'd start by pulling the OS disk out and hooking it to a non-Highpoint
controller and ensure it boots.  Chances are it will.

Some advice, assuming you haven't done this before:

1) Make note of what your filesystem layout is before migrating.  "df"
output should be sufficient.

2) When you boot it, FreeBSD will probably complain "unable to determine
root filesystem".  I'm guessing these are ATA/SATA disks.  The kernel
messages shown should list off what ATA disks are attached, and you'll
have to make some educated guesses as to what it is, e.g. ufs:ad4s1a
rather than the old ufs:da0s1a.  You'll have to mount all the
filesystems by hand (mount /dev/ad4s1d /var, etc. -- this is what #1 was
for :-) ) so you can get access to vi, so you can vi /etc/fstab and fix
the problem.

You can also use ed(1) to do the fstab editing without having to mount
everything, if you're familiar with it.

Hope this helps.

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |