Linux Backup Solutions

I've been looking for the best Linux backup system, and also reading lots of HN comments.

Instead of putting pros and cons of every backup system I'll just list some deal-breakers which would disqualify them.

Also I would like that you, the HN community, would add more deal breakers for these or other backup systems if you know some more and at the same time, if you have data to disprove some of the deal-breakers listed here (benchmarks, info about something being true for older releases but is fixed on newer releases), please share it so that I can edit this list accordingly.

Amanda (comments by sammcj)

It has a lot of management overhead and that's a problem if you don't have time for a full time backup administrator.
It mainly comprises of using tar for backups which is pretty inflexible by modern standards.
The enterprise web interface is OK but it's had so many bugs it's not funny.
Backups are very slow.
Restores are slow and painful to manage.
I haven't found it to be great when trying to integrate with puppet / automation frameworks.

Bacula (from the Why section on Burp):

Too complex to configure
Stores catalog separate from backups, need to backup catalog
Doesn't deduplicate
Relies on clock accuracy
Can't resume an interrupted backup
Retention policy

Snebu:

Doesn't do encryption
File level, not block level deduplication

Obnam:

Really slow for large backups (from a benchmark between obnam and attic)
To improve performance:

lru-size=1024
upload-queue-size=512

as per: http://listmaster.pepperfish.net/pipermail/obnam-support-obnam.org/2014-June/003086.html

Burp:

Client side encryption turns off delta differencing

Bup:

Can't purge old backups
Doesn't encrypt backups (well, there is encbup)

Tarsnap:

Slow restore performance on large backups? (Sorry Colin aka cperciva)
This was a really strong candidate until I read some comments on HN about the slow performance to restore large backups.
If this has changed in a recent version or someone has benchmarks to prove or disprove it, it would be really valuable.

Duplicity:

Slow restore performance on large backups?
This was also a really strong candidate until I read some comments on HN about the slow performance to restore large backups.
If this has changed in a recent version or someone has benchmarks to prove or disprove it, it would be really valuable.

BackupPC:

It doesn't do encrypted backups

backup2l:

No support for encryption

Arq:

Just included here because I knew someone would mention it in the comments. It's Mac OS X only. This list is for Linux server backup systems.

Other contenders (of which I don't have references or information):

Also Tarsnap scores really high on encryption and deduplication but it has 3 important cons:

Not having control of the server where your backups are stored
Bandwith costs make your costs unpredictable
The so called Colin-Percival-gets-hit-by-a-bus scenario

Attic

Attic has some really good comments on HN and good blog posts, doesn't have any particular deal-breaker (for now, if you have one please share with us), so for now is the most promising.

Roll your own

Some HN users have posted the simple script they use. The scripts usually use a combination of

FROM=/etc
TO=/var/backups
LINKTO=--link-dest=$TO/`/usr/bin/basename $FROM`.1
OPTS="-a --delete -delete-excluded"
NUMBER_OF_BACKUPS=8

find $TO -maxdepth 1 -type d -name "`basename $FROM`.[0-9]"| sort -rn| while read dir
do
        this=`expr match "$dir" '.*\([0-9]\)'`; 
        let next=($this+1)%$NUMBER_OF_BACKUPS;
        basedirname=${dir%.[0-9]}
        if [ $next -eq 0 ] ; then
                 rm -rf $dir
        else
                 mv $dir $basedirname.$next
        fi
done
rsync $OPTS $LINKTO $FROM/ $TO/`/usr/bin/basename $FROM.0`

zx2c4's script

zx2c4@thinkpad ~ $ cat Projects/remote-backup.sh 
    #!/bin/sh
    
    cd "$(readlink -f "$(dirname "$0")")"
    
    if [ $UID -ne 0 ]; then
            echo "You must be root."
            exit 1
    fi
    
    umount() {
            if ! /bin/umount "$1"; then
                    sleep 5
                    if ! /bin/umount "$1"; then
                            sleep 10
                            /bin/umount "$1"
                    fi
            fi
    }
    
    unwind() {
            echo "[-] ERROR: unwinding and quitting."
            sleep 3
            trace sync
            trace umount /mnt/mybackupserver-backup
            trace cryptsetup luksClose mybackupserver-backup || { sleep 5; trace cryptsetup luksClose mybackupserver-backup; }
            trace iscsiadm -m node -U all
            trace kill %1
            exit 1
    }
    
    trace() {
            echo "[+] $@"
            "$@"
    }
    
    RSYNC_OPTS="-i -rlptgoXDHxv --delete-excluded --delete --progress $RSYNC_OPTS"
    
    trap unwind INT TERM
    trace modprobe libiscsi
    trace modprobe scsi_transport_iscsi
    trace modprobe iscsi_tcp
    iscsid -f &
    sleep 1
    trace iscsiadm -m discovery -t st -p mybackupserver.somehost.somewere -P 1 -l
    sleep 5
    trace cryptsetup --key-file /etc/dmcrypt/backup-mybackupserver-key luksOpen /dev/disk/by-uuid/10a126a2-c991-49fc-89bf-8d621a73dd36 mybackupserver-backup || unwind
    trace fsck -a /dev/mapper/mybackupserver-backup || unwind
    trace mount -v /dev/mapper/mybackupserver-backup /mnt/mybackupserver-backup || unwind
    trace rsync $RSYNC_OPTS --exclude=/usr/portage/distfiles --exclude=/home/zx2c4/.cache --exclude=/var/tmp / /mnt/mybackupserver-backup/root || unwind
    trace rsync $RSYNC_OPTS /mnt/storage/Archives/ /mnt/mybackupserver-backup/archives || unwind
    trace sync
    trace umount /mnt/mybackupserver-backup
    trace cryptsetup luksClose mybackupserver-backup
    trace iscsiadm -m node -U all
    trace kill %1

pwenzel suggests

  rm -rf backup.3
  mv backup.2 backup.3
  mv backup.1 backup.2
  cp -al backup.0 backup.1
  rsync -a --delete source_directory/  backup.0/

and https://gist.github.com/ei-grad/7610406

Meta-backup solutions (which use several backup solutions)

IngussNeilands/gist:0550a1916ac97bf1f18028d78744af98