|
EnGarde Secure Linux - Hard Disk Recovery
HowTo
Objective
This procedure was
tested by copying a working EnGarde installation from a 6.4GB drive to
a 2.1GB drive that replaced it in the same machine. The archive was created
on and restored from an NFS mount. Other media are equally valid; for
example, tape, or a third physical drive.
It helps to understand
the procedure below if you know that the machine this was tested on is
named "cypress", and the NFS host is "sequoia".
It is assumed that
the reader is familiar operating as the root user and knows how to use
a text editor such as vi(1) or pico(1). This document applies to EnGarde
Linux 1.0.1 (Finestra).
The proper forum to
ask questions is one of the "EnGarde Mailing Lists" (see "Resources"
below). Should you have any issues with the steps below, please send an
email to the 'engarde-users' list.
Additional
Software Required
A Linux-on-a-floppy
boot/rescue disk. We recommend tomsrtbt (Toms Root Boot Disk), available
at:
http://www.toms.net/rb/home.html
This procedure was
tested with version 1.7.361.
Summary
Procedure
1. Boot with tomsrtbt
and tar everything to other media.
2. Replace the machine's disk drive.
3. Reboot with tomsrtbt and partition and format the new drive.
4. Restore everything from the archive media.
Disk
Configuration
EnGarde is
installed by default into four partitions as follows:
/dev/hda1 swap
/dev/hda2 /
/dev/hda3 /home
/dev/hda4 /var
In the procedure
below, EnGarde is reinstalled onto a single partition, resulting in
the following configuration:
/dev/hda1 Swap
/dev/hda2 /
This is acceptable
for the intended use of the machine tested here. However, this procedure
could be modified to change the partitioning to any desired scheme,
including one with multiple disks. To do this, create the necessary
directories and mount the various partitions on them as desired. Create
only the directories actually needed for this; for example, a separate
disk could be used for /var/spool/mail. A sample configuration might
be:
/dev/hda1 swap
/dev/hda2 /
/dev/hda3 /home
/dev/hda4 /var
/dev/hdb1 /var/spool/mail
User
and Group Considerations
The first
time I did this, I lost file ownership information. This may be
because I used the wrong arguments to tar (actually pax on tomsrtbt),
but I
solved the problem by making certain all EnGarde users were valid in the
tomsrtbt configuration. This is easy, because tomsrtbt defines only three
users and one group; simply merge the files as shown below.
Unix
Socket Considerations
Unix sockets
(mode srw-rw-rw-) do not archive properly; they lose the 's' and become
ordinary files. EnGarde comes with a number of programs that use these
sockets. Some of them, notably postfix, recognize this problem and re-create
the sockets as necessary. Others do not. In particular, syslog-ng does
NOT.
What this means
is that when you start the machine on the new drive, logging does not
work at all. To fix this, the sockets must be deleted before the machine
is rebooted so they can be recreated. The details are listed below.
Detailed
Procedure
1. Boot with
tomsrtbt and go to the /mnt directory:
# cd /mnt
2. Mount the drive
to be copied:
# mkdir cypress
# mount -t ext2 /dev/hda2 cypress
# mount -t ext2 /dev/hda3 cypress/home
# mount -t ext2 /dev/hda4 cypress/var
2. Mount the temporary
storage drive:
# mkdir sequoia
# mount -t nfs -o rsize=8192 -o wsize=8192 sequoia:/home sequoia
3. Fix up the passwd
and group files, and save copies:
# grep -v root
cypress/etc/passwd | grep -v shutdown | grep -v halt >>/etc/passwd
# grep -v root:: cypress/etc/group >>/etc/group
or
# cp cypress/etc/group /etc/group
# cp /etc/passwd sequoia
# cp /etc/group sequoia
4. Create the archive:
# cd cypress
# pax -w -p e -f /mnt/sequoia/cypress.tar .
5. Power off the
machine, and physically exchange the drives.
Note: Make sure
that the BIOS recognizes the new drive.
6. Boot with tomsrtbt
and prepare the new drive:
# dd if=/dev/zero
of=/dev/hda bs=512 count=1
# fdisk <create whatever partitions are needed>
# mkswap /dev/hda1
# mke2fs /dev/hda2 <repeat as required>
7. Mount the partitions
to be restored:
# cd /mnt
# mkdir cypress
# mount -t ext2 /dev/hda2 cypress
# rmdir lost+found
8. Mount the temporary
storage drive:
# mkdir sequoia
# mount -t nfs -o rsize=8192 -o wsize=8192 sequoia:/home sequoia
9. Fix up the password
and group files again:
# cp sequoia/passwd
/etc
# cp sequoia/group /etc
10. Restore the
archive to the new drive:
# cd cypress
# pax -r -p e -f /mnt/sequoia/cypress.tar
11. Perform post-installation
procedures:
# rm dev/log
# rm var/chroot/named/dev/log
# vi etc/fstab <modify to match new partitioning scheme>
12. Install the
boot partition and reboot (remove floppy!):
# chroot /mnt/cypress
/sbin/lilo
# shutdown -r now
That's it; the machine
should be just as it was when you last powered it down.
Disclaimer
Guardian Digital shall
not be liable in contract, tort (including without limitation negligence),
breach of any statutory duty and/or any law for any direct special indirect
consequential damages and/or loss including, but not limited to, loss
of data loss of profits loss of business arising from or in connection
with this or any other documents viewed at www.engardelinux.org.
In other words, backup
all critical data before attempting any system changes, and enjoy!
Acknowledgements
The core of this technique
came from
Unix Backup
& Recovery
First Edition, November 1999
W. Curtis Preston
ISBN: 1-56592-642-0
Published by O'Reilly
Document provided
and written by Marcus
Redivo
|
