How to backup a multi user linux file server over a network, using rsync or similar

Question

My first post on here.

I am trying to backup all data files from one server to another. The data can be owned by several users or by reserved nologin users.

I am trying to create a remote mirror of all users files. Ready for restoring at a later date.

I have searched on here and lots of googling but all the solutions involve changing ownership of the file or other fiddles.

I have samba and nfs(export) shares.

The system is 2 raspberry PIs each with several multibay usb drives, so raspbian/debian based.

My best solution so far is:

cat /etc/scripts/backup_data4.sh

if [ -e /mnt/data4_B/B4 ]; then
    printf "There is a B4 marker\n"
    sudo rsync -avz -e ssh /mnt/data4/git /mnt/data4_B/
    sudo rsync -avz -e ssh /mnt/data4/stacking2 /mnt/data4_B/

else
    printf "B4 does not exist\n"
fi

where /mnt/data4_B is a mounted exported drive on backup server.

/etc/exports

/mnt/data1/      192.168.0.160(rw,sync,no_subtree_check)
/mnt/data2/      192.168.0.160(rw,sync,no_subtree_check)
/mnt/data3/      192.168.0.160(rw,sync,no_subtree_check)
/mnt/data4/      192.168.0.160(rw,sync,no_subtree_check)


/mnt/data5/      192.168.0.160(rw,sync,no_subtree_check)
/mnt/data6/      192.168.0.160(rw,sync,no_subtree_check)
/mnt/data7/      192.168.0.160(rw,sync,no_subtree_check)
/mnt/data8/      192.168.0.160(rw,sync,no_subtree_check)

This script does work to a point but I have lots of issues with ownership and permissions on the backup server.

Any suggestions welcome. Thanks.

Extra Added.

user names, UID and GID are identical on both systems.

I can't find any way to use:

 rsync -av fromdir user@server:todir

that can handle multiple users files.

Answer 1

If data4_B is a mounted NFS share root can just copy everything preserving ownership and attributes, only root can do that for other users:
sudo cp -a /mnt/data4/git /mnt/data4_B/

rsync can do that as well using only ssh without mounted shares but you first need to make sure root can log in via ssh on the remote machine. So fist do a ssh-copy-id from the one root account to the other. Then your rsync -av fromdir user@server:todir will work if user can log in.

The -e you wrote about is used like so:
sudo rsync -e "ssh -p 22 -l root" -av /mnt/data4/git "host.example.com:/mnt/data4_B"

Answer 2

The main one you may be missing is -A or --acls to include file ACLs, which rsync excludes by default. I use the flags below for backing up with permissions.

# copy data over, ignoring mount points, sparse files, etc:
# -A should include --acls (check it though)
# [optional] -S sparse, -H hard-links, -x don't follow mounts, -v verbose
# -a (archive) includes -r/l/p/t/g/o/D 

rsync -SHAxa /mnt/some/folder/ /mnt/backups/

---

Additionally, you should not need to use -e ssh when /mnt/data4/git and /mnt/data4_B/ are both "local" paths

Answer 3

Thanks for all the suggestions, they led me to a solution.

The issue was that only the file owner can set/change the ownership of the nfs file or directory.

I still don't understand why root can't change ownership of the mounted remote drive.

I also had a samba mis-configuration that caused many files to have the wrong user. I removed all use of admin user from the config file.

My final solution was to run the backup script on the backup server pulling the files from the master server.

sudo rsync -avx /mnt/data4_A/git /mnt/data4/

where data4_A is the remote nfs drive on server A and data4 is the local disk in the backup server B.

Thank for all your help.