[rear-users] How to config REAR with dual-OS boot and LTO-6 tape drive?

George Anchev studio at anchev.net
Mon Jul 18 18:27:17 CEST 2016


Hi,

I have recently discovered REAR and I am looking for the most relevant
options/config to use it for my system. My final goal is to have a healthy
DR backup + up-to-date backup of all files changed after it, so I can
restore quickly and easily my information in case of trouble.


*Background:*

I have a Dell PowerVault LTO-6 tape drive connected through a SAS
controller:

# lspci | grep -i sas
02:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic SAS2008
PCI-Express Fusion-MPT SAS-2 [Falcon] (rev 03)

Currently I am using the tape drive for daily backup and archiving with
Bacula 7.4.2 software.


My system has 3 SATA hard drives (sda-sdc) and 1 SATA SSD (sdd). The
partitions and OS installs are as follows:

/dev/sda1 - NTFS partition used for scratch
/dev/sdb1 - NTFS partition used for Windows 7 user directory, program
settings and other things that should not scratch the SSD
/dev/sdb2 - linux swap
/dev/sdb3 - /var (ext4)
/dev/sdb4 - /home (ext4)
/dev/sdc2 - NTFS partition used for daily project files
/dev/sdd1 - /boot/efi (vfat)
/dev/sdd3 - NTFS - Windows 7 installation (C:)
/dev/sdd4 - /boot (ext4)
/dev/sdd5 - / (ext4) - root partition for openSUSE Leap 42.1 installation

I don't need backup for sda1, it's a scratch disk.

I already have a daily schedule in Bacula which backs up important files
from:

sdb1
sdb3
sdb4
sdc2
sdd3
sdd5

+ some other files from a small local network (other Bacula FD clients).


My questions are:

*1. What should I backup?*

Considering the above explanations I suppose that for a good disaster
recovery I need to backup everything except sda1 and sdb2. On the other
hand for *some* of the other partitions I already have a daily backup, so
it makes no sense to create a full REAR backup on a daily basis, right?
That's why I assume that for DR I need to backup only the disk/partition
layout + the system files. Then upon restore I will have to somehow A)
restore the system (both Linux and Windows) B) restore the rest from Bacula
tape volumes.

Is that correct?

*2. How am I to organize such a backup scheme?*

After reading the documentation I see that when Bacula and tape is in the
game, I should set:

BACKUP=BACULA
OUTPUT=OBDR
TAPE_DEVICE=/dev/nst0

but considering that my LTO-6 drive is not a ODBR device, obviously I
cannot use OUTPUT=OBDR + I would also need a separate boot media (USB,
DVD...) as it is not possible to boot from this LTO device. So what should
I set in OUTPUT? ISO? Anything else? (I am willing to keep the main backup
on tape)

*3. If I use Bacula for backup to tape, how exactly is this supposed to
work?*

Bacula uses a database, there are also other backup pools and volumes etc.
It's a complex system. Or does REAR somehow create an independent isolated
backup which is unrelated to Bacula's daily backup jobs? Where should the
bootstrap file be saved?

It is quite unclear to me how exactly this can work without conflicts and
complications although I have read the full Bacula and REAR documentations.

*4. Do I need Bacula at all if I want to have a DR backup on tape? Can REAR
do it independently?*

*5. When tape backup is used - what boot media would you recommend?*

I don't use NFS and I know that DVDs are not long term proof. Also USB
sticks are perhaps not the most reliable media. I wonder what you would
recommend.

*6. How will REAR restore such a system?*

Will it recreate the EFI entries, all GPT partitions and Windows
installation too? Or will it work only for the Linux stuff? What will
happen during restore considering that after REAR's backup I will continue
to do my daily backups with Bacula, i.e. it's database will grow and backup
itself and after a DR recovery it will be overwritten.

Also how am I supposed to proceed in case only one hard drive fails, i.e. I
don't want to restore and overwrite the information on the healthy ones.

*7. Is there a safe way to test all this without damaging the system or
files during restore?*

I am using KVM and I could probably set up a VM guest with similar
structure for the purpose. However I am not sure how REAR would work inside
such system and if a SAS passthrough would work in order to forward the
tape device to the VM guest. Has anyone tested that?


Sorry for the lengthy email. I am just trying to avoid any potential
mistakes and I hope someone can shed some light in my search :)


Thanks!

--
George
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