turbine2
Posts: 51
Joined: Thu Dec 06, 2012 11:21 am

RSYNC and symlinks

Mon Aug 17, 2020 2:02 pm

Hi everyone,
I've had a look around and I can't see anything directly that looks like this problem.

I have a raspberry pi (what a surprise) that I want to back up the SD card to as a hot backup. To do this I have a mount on an ASUSTOR NAS that is mounted to \mnt\backups\

The FSTab entry is this:-

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//xxx.xxx.xxx.xxx/Backups /mnt/backup cifs username=xxxxxx,password=xxxxxxxx,vers=3.0,users,auto,user_xattr,sfu 0 0
As I understand it the sfu option should allow me to backup the symlinks, however when I run the script to backup I get the following error for several of the files

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rsync: symlink "/mnt/backup/piserver/lib/systemd/system/fuse.service" -> "/dev/null" failed: Operation not supported (95)
The rsync line I am using is:-

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rsync -avH --delete-during --delete-excluded --exclude-from=/usr/bin/rsync-exclude.txt / /mnt/backup/$HOSTNAME/
I'm guessing that this is a limitation of the ASUSTOR rsync, but wanted to check if there is something else I should be looking at.

Also, is there a way that I can force fstab to use the IPV4 address rather than the IPV6 one? I can resolve both, but the IPV6 is external so routing becomes an issue.

Many thanks,

David
David

Kendek
Posts: 265
Joined: Thu Jul 25, 2019 4:39 pm
Location: Kaposvár, Hungary

Re: RSYNC and symlinks

Mon Aug 17, 2020 2:41 pm

/etc/rsyncd.conf:

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uid = root
gid = root
read only = false
use chroot = no
dont compress = *

[backups]
path = /Backups

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> rsync -aAXxh --progress --delete / 192.168.1.x::backups
or reverse:

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uid = root
gid = root
read only = false
use chroot = no
dont compress = *

[system]
path = /

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> rsync -aAXxh --progress --delete 192.168.1.x::system /Backups

turbine2
Posts: 51
Joined: Thu Dec 06, 2012 11:21 am

Re: RSYNC and symlinks

Tue Aug 18, 2020 1:59 pm

Um, I'm not sure what you're telling me there, would you mind expanding on that and how it solves my symlinks problem please?
David

bls
Posts: 862
Joined: Mon Oct 22, 2018 11:25 pm
Location: Seattle, WA
Contact: Twitter

Re: RSYNC and symlinks

Tue Aug 18, 2020 2:17 pm

turbine2 wrote:
Tue Aug 18, 2020 1:59 pm
Um, I'm not sure what you're telling me there, would you mind expanding on that and how it solves my symlinks problem please?
He's suggesting a different method of accessing files on a remote system using rsync, instead of using CIFS. This will work well if xxx.xxx.xxx.xxx is a Linux system of some sort that you can start the rsyncd service on. 'man rsyncd.conf' will give you details on the config file.

If you are able to start an rsyncd service on your ASUSTOR, rsyncd would be a much better way to go than using CIFS.

You might be able to make your backups work with your current configuration if you review the rsync command format carefully (man rsync), especially the switches "-l" (lower case L), -L, --copy-unsafe-links, --safe-links, --munge-links, --copy-dirlinks, and --keep-dirlinks.Sorry, I've not actually used any of these, but looking at 'man rsync' and searching for symlink, these all popped up.
Pi tools:
Quickly and easily build customized-just-for-you SD Cards: https://github.com/gitbls/sdm
Easily run your network's DHCP/DNS on a Pi: https://github.com/gitbls/ndm
Easy strongSwan VPN installer/manager: https://github.com/gitbls/pistrong
Lightweight Virtual VNC Config: https://github.com/gitbls/RPiVNCHowTo

Kendek
Posts: 265
Joined: Thu Jul 25, 2019 4:39 pm
Location: Kaposvár, Hungary

Re: RSYNC and symlinks

Tue Aug 18, 2020 2:39 pm

Yes, or use rsync over SSH, but not CIFS or any other similar protocol. Rsyncd is the best choice inside local network for compatibility and performance reasons. SSH may be a bit slower due to encryption.

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> rsync -aAXxh --progress --delete / root@192.168.1.x:/Backups

turbine2
Posts: 51
Joined: Thu Dec 06, 2012 11:21 am

Re: RSYNC and symlinks

Fri Aug 21, 2020 7:14 pm

Ah, I see, thank you for the clarification. I think the Asustor uses busybox Linux as it’s o/s. I will have a look at those options.

Thanks for the help.
David

turbine2
Posts: 51
Joined: Thu Dec 06, 2012 11:21 am

Re: RSYNC and symlinks

Tue Sep 15, 2020 9:42 am

Thanks to Kendek and bls I have managed to fix this.

In the end I scrapped the idea of using a mounted share to do the rsync and used SSH key logins between the Pi and the Asustor to do the rsync backup. Unfortunately due to the 'security settings' of the Asustor I have to do that a the Asustor's root user rather than the backup user I intended but it's working now.

Goodness only knows why I started down the route of a mounted drive because that's not how I use rsync on other systems.
David

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