[Linux] Journal.

A while ago we bought an 80GB external usb harddisk for storing backups. After tediously archiving the files by hand for a couple of months we finally decided to look for a tool to do incremental backup for us automatically.

First, a look at the limitations of our old methods for dumping the filesystem: using tar or dump.

tar

• It doesn’t support multiple volumes with file output (with -M option, it overwrites the file) - that was our 4GB limitation with FAT32 partition
• I don’t know how to handle differential backups efficienly
• No automation

dump

• Works only on ext2/3 filesystems
• Incremental backups are trivial (based on the date only)
• Little automation

Having a quick look at what’s available in debian repositories we found a nice little tool called backup2l. It’s essentially just a shell script, but is just what we needed.

It’s as simple as install, configure and run. We changed the following main configuration options and left the rest to default.

# list of directories to backup
SRCLIST=(/etc /root /home /var/ /usr/local /work /packages /usr/src/config /mnt/shared/work /mnt/shared/mail /mnt/shared/drivers)
# Mount point of backup device
BACKUP_DEV="/mnt/backup"
# backup directory
BACKUP_DIR="/mnt/backup/orta-backup"
# uncomment the following to backup installed packages in debian
    echo "  writing dpkg selections to /root/dpkg-selections.log..."
    dpkg --get-selections | diff - /root/dpkg-selections.log > /dev/null || dpkg --get-selections > /root/dpkg-selections.log
#UNCONFIGURED=1
CREATE_DRIVER=DRIVER_TAR

Create the mount point for the backup drive if haven’t already done so,

/dev/sda1       /mnt/backup     reiserfs        rw,noauto       0       0

backup2l can also mount the external mountpoint automatically, which is great, although it doesn’t work for us - our USB drive has a problem: if the usb_storage module was loaded before we connect the external storage it may not work, so need to rmmod usb_storage first then plug it again.

To backup just run,

$ backup -b [backup level]

It looks at existing repositories and performs an incremental backup at a given level or a full backup. The repositories are updated accordingly.

To restore files run,

$ backup -r [pattern]

It is also posssible to restore files at a given time with the -t option.

backup2l also installs a cron script to /etc/cron.daily/zz-backup2l. Comment out if you don’t want to run scheduled backups, which is true in our case since the backup drive is not always connected.

This entry was posted on Sunday, October 10th, 2004 at 11:31 pm and is filed under Application, System. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.