On Wed, Mar 7, 2012 at 8:55 AM, <gand...@d-danks.co.uk> wrote:
>> 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
>>
>>
> Hi,
> Why don't you something like bind mount the folders you want to copy
> and rsync them to the eSATA disk, after creating a similar partition
> layout on it. Remember to exclude system files like /proc/*, /dev/*
> and /sys/* as well as the ones you want to exclude yourself from the
> rsync. When you want to sync the clone again just do the same again
> and rsync the changes.
>
> Regards,
> Derek
>
>
As an added note on this, rsync's --one-file-system (-x) flag is handy
for avoiding grabbing unneeded things, but will typically leave you
without the base few device nodes needed to boot the backup, those can
either be grabbed from a stage3, or created with (courtesy of Linux
>From Scratch's section "6.2.1. Creating Initial Device Nodes"):
mknod -m 600 ${backup}/dev/console c 5 1
mknod -m 666 ${backup}/dev/null c 1 3
--
Poison [BLX]
Joshua M. Murphy
