[gentoo-user] Clone live system as a simple backup?

[Mark Knecht]

Hi,
   I'm interested in the idea of cloning a live, complicated hardware
system onto a single external hard drive as a simple backup. I would
like this external drive to be completely bootable. What's the best
way to approach doing this? I was considering just doing a Gentoo
install from scratch but figured maybe there's a way to clone enough
of the live system to get me there less painfully?

   The system I'm playing with has five 500MB hard drives with most
partitions in linked together in various forms of RAID. (1, 5 & 6)
That said, the total storage that this system presents KDE and the
users is about 600GB.

   I have an external 1TB eSATA drive which is therefore large enough
to hold everything on this system, albeit without the reliability of
RAID which is fine for this purpose.

   The system looks more or less like:

/dev/sda1 -> /boot (50MB)
/dev/sdb1 -> /boot copy
/dev/sdc1 -> /boot copy

c2stable ~ # df
Filesystem     1K-blocks      Used Available Use% Mounted on
rootfs          51612920  31862844  17128276  66% /
/dev/root       51612920  31862844  17128276  66% /
rc-svcdir           1024        92       932   9% /lib64/rc/init.d
udev               10240       476      9764   5% /dev
shm              6151284         0   6151284   0% /dev/shm
/dev/md7       389183252 350247628  19166232  95% /VirtualMachines
tmpfs            8388608         0   8388608   0% /var/tmp/portage
/dev/sda1          54416     29516     22091  58% /boot
c2stable ~ # cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5]
[raid4]
md6 : active raid5 sdb6[1] sdc6[2] sda6[0]
      494833664 blocks super 1.1 level 5, 64k chunk, algorithm 2 [3/3]
[UUU]

md7 : active raid6 sdb7[1] sdc7[2] sda7[0] sdd2[3] sde2[4]
      395387904 blocks super 1.2 level 6, 16k chunk, algorithm 2 [5/5] [UUUUU]

md3 : active raid6 sdb3[1] sdc3[2] sda3[0] sdd3[3] sde3[4]
      157305168 blocks super 1.2 level 6, 16k chunk, algorithm 2 [5/5] [UUUUU]

md126 : active raid1 sdc5[2] sda5[0] sdb5[1]
      52436032 blocks [3/3] [UUU]

unused devices: <none>
c2stable ~ #

   /dev/md3 is a second Gentoo installation that doesn't need to be
backed up at this time. md6 is an internal RAID used to back up md7
daily. It doesn't need to be backed up, but if the machine totally
failed killing all the drives that wouldn't survive so currently I
back up md126 to md6 daily, and then back up md6 weekly to an external
eSATA drive.

   What I'd like to do is clone

1) /boot (sda1) including grub and everything required to make it bootable
2) back up the system portions of dev/md126 (/ )
3) Add some swap space on the external drive
4) back up /dev/md7 which is all of my VMs
5) back up /home to a separate partition on the external drive
6) back up some special things like /var/lib/portage/world and
/usr/portage/packages

My thought is that this drive is basically bootable, but over time
gets out-of-sync with the system. However should the system fail I've
got a bootable external drive with all the binary packages required to
get it running again quickly. However I can always boot the drive, do
an emerge -ek @world, and basically be back to where I am as of the
last backup.

The external drive will look something like:

/dev/sdg1 -> /boot
/dev/sdg2 -> swap
/dev/sdg3 -> / (not including /home, /usr/portage/distfiles, etc)
/dev/sdg5 -> /usr/portage/packages
/dev/sdg6 -> /dev/md7

etc....

   I will of course have to modify grub.conf and /etc/fstab to work
from this drive but that's no big deal.

   What are folks best ideas about how to approach doing something like this?

Thanks,
Mark