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We will be using FreeSBIE to do the data transfer between the old and new HDD. Why? It is easier to copy an HDD
when it is unused and with no chance of the data being modified. In short, the system is offline and copying
the HDD is guaranteed to be correct.
From there, I used the instructions for Swapping boot drives around, written
way back in August 1999. All I needed was the details for tar'ing up one file system and untar'ing it on the other.
For this clean and easy technique, I will boot from something other than the SATA drive
and the two IDE RAID drives. I could have used an HDD which already had FreeBSD on it.
I choose instead to use a FreeSBIE live CD. FreeSBIE 2.0 gives me FreeBSD
6.2 and all the tools I need to massage the data according to my will.
First, I boot up the system from the CD. Then I su to root, and move to my home directory.
Then I create two directories:
mkdir new old
These two directories will form the starting point for my transfers. I will mount the existing SATA drive
under the old directory and the new RAID-1 system under the new directory.
I need mount points for the various slices. So I did this:
cd old
mkdir root var tmp usr
cd ..
cd new
mkdir root var tmp usr
As you will see in the problems section later on, I forgot to do this, but you won't:
chmod 1777 ~/old/tmp
I started sysinstall and then used it to configure the new HDD (twed0). I click on the following links
once in sysinstall:
- Configure | Fdisk | twed0 | A = Use Entire Disk | W = Write Changes | Yes |
Standard Install a standard MBR (no boot manager)
That will run fdisk on the new HDD. When completed , press Q - Quit and then Cancel
to get back to the FreeBSD Configuration Menu
I will now label the new HDD. Again, from the FreeBSD Configuration Menu, I click on Label.
Ensure the right disk is selected, twed0 in my case.
Now I will create several slices and assign them some mount points. sysinstall will actually
mount the slices at the mount points specified, and which we created earlier in this process.
The short hand here is:
C = Create | 1 GB | FS | /mnt/root
C = Create | 2 GB | swap
C = Create | 2 GB | FS | /mnt/tmp
C = Create | 2 GB | FS | /mnt/var
C = Create | All (142GB) | FS | /mnt/usr
W = Write
Yes
Here is what the screen looked like after issuing the Write command.
FreeBSD Disklabel Editor
Disk: twed0 Partition name: twed0s1 Free: 0 blocks (0MB)
Part Mount Size Newfs Part Mount Size Newfs
---- ----- ---- ----- ---- ----- ---- -----
twed0s1a /mnt/root 1024MB UFS2+S Y
twed0s1b swap 2048MB SWAP
twed0s1e /mnt/tmp 2048MB UFS2+S Y
twed0s1f /mnt/var 2048MB UFS2+S Y
twed0s1g /tmp/usr 142GB UFS2+S Y
And in case it helps you, here are the the mounted filesystems:
[dan@ngaio:/mnt] $ mount
/dev/ad6s1a on / (ufs, local)
devfs on /dev (devfs, local)
/dev/ad6s1e on /tmp (ufs, local, soft-updates)
/dev/ad6s1f on /usr (ufs, local, soft-updates)
/dev/ad6s1d on /var (ufs, local, soft-updates)
fdescfs on /dev/fd (fdescfs)
polo:/usr/ports/distfiles on /usr/ports/distfiles (nfs)
/dev/twed0s1a on /mnt/root (ufs, local, soft-updates)
/dev/twed0s1e on /mnt/tmp (ufs, local, soft-updates)
/dev/twed0s1f on /mnt/var (ufs, local, soft-updates)
/dev/twed0s1g on /tmp/usr (ufs, local, soft-updates)
[dan@ngaio:/mnt] $
I will not be copying over devfs or fdescfs. NFS mounts should also
not be copied over. In short, look only for the mount points associated
with the HDD in question. In this case, ad6.
Of note were some interesting directories I had never seen before:
[dan@ngaio:/mnt] $ find .
.
./tmp
./tmp/.snap
./var
./var/.snap
./root
./root/.snap
./usr
[dan@ngaio:/mnt] $
What are those files? A Google found me a answer.
In short, see man dump(8)
and read the -L option.
Here is how I mounted the various slices of the SATA drive:
mount /dev/ad6s1a ~/old/root
mount /dev/ad6s1e ~/old/tmp
mount /dev/ad6s1f ~/old/var
mount /dev/ad6s1d ~/old/usr
Similarly, for the new RAID-1 cluster:
mount /dev/twed0s1d ~/new/root
mount /dev/twed0s1e ~/new/tmp
mount /dev/twed0s1f ~/new/var
mount /dev/twed0s1g ~/new/usr
Everything is ready. Let's transfer the data. I will do this one file system at a time. Let's
start with the root partition:
tar --one-file-system -c -f - -C ~/old/root/ . | tar xpvf - -C ~/new/root/
The tar on the left will do a cd to ~/old/root/ and start tar'ing everything up, staying
within the one file system. The -c is to create. The -f designates the output file, this case
STDOUT.
The tar on the right will take extract, retain permissions, and display each file name as it is extracted.
The -f - indicates STDIN as the source of the tarball. tar will do a cd to ~/new/root before it starts
this process.
This process needs to be repeated for each mount point:
tar --one-file-system -c -f - -C ~/old/var/ . | tar xpvf - -C ~/new/var/
tar --one-file-system -c -f - -C ~/old/tmp/ . | tar xpvf - -C ~/new/tmp/
tar --one-file-system -c -f - -C ~/old/usr/ . | tar xpvf - -C ~/new/usr/
That sounds just too easy. Well, there is one gotcha. If anything refers to the old HDD
by device, then it will break. You must change the new /etc/fstab before you reboot from the
new RAID array. In my case, the file I need to edit is ~/new/root/etc/fstab and the changes required
reflect what happened when I was using the Disk Label Editor. That is, I made sure that /dev/twed0s1a
was mounted at /, twed0s1b was swap, twed0s1e was mounted at /tmp, etc.
Then I shutdown the system with a shutdown -p now and disconnected the SATA drive.
During the power up process, I removed the FreeSBIE CD from the CD drive and let the system
boot from the RAID card. Apart from the minor permission problem mentioned below, it went
flawlessly.
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