6.4. Backup ext2/3/4 File Systems

Procedure 6.1. Backup ext2/3/4 File Systems Example

1. All data must be backed up before attempting any kind of restore operation. Data backups should be made on a regular basis. In addition to data, there is configuration information that should be saved, including /etc/fstab and the output of fdisk -l. Running an sosreport/sysreport will capture this information and is strongly recommended.

   # cat /etc/fstab
   LABEL=/            /               ext3    defaults        1 1
   LABEL=/boot1       /boot           ext3    defaults        1 2
   LABEL=/data        /data           ext3    defaults        0 0
   tmpfs              /dev/shm        tmpfs   defaults        0 0
   devpts             /dev/pts        devpts  gid=5,mode=620  0 0
   sysfs              /sys            sysfs   defaults        0 0
   proc               /proc           proc    defaults        0 0
   LABEL=SWAP-sda5    swap            swap    defaults        0 0
   /dev/sda6          /backup-files   ext3    defaults        0 0
   
   # fdisk -l
      Device Boot    Start      End    Blocks      Id  System
   /dev/sda1 *           1       13    104391      83  Linux
   /dev/sda2            14      1925   15358140    83  Linux
   /dev/sda3          1926      3200   10241437+   83  Linux
   /dev/sda4          3201      4864   13366080    5   Extended
   /dev/sda5          3201      3391   1534176     82  Linux swap / Solaris
   /dev/sda6          3392      4864   11831841    83  Linux
   

   In this example, we will use the /dev/sda6 partition to save backup files, and we assume that /dev/sda6 is mounted on /backup-files.
2. If the partition being backed up is an operating system partition, bootup your system into Single User Mode. This step is not necessary for normal data partitions.
3. Use dump to backup the contents of the partitions:

   Note

   • If the system has been running for a long time, it is advisable to run e2fsck on the partitions before backup.
   • dump should not be used on heavily loaded and mounted filesystem as it could backup corrupted version of files. This problem has been mentioned on dump.sourceforge.net.

     Important

     When backing up operating system partitions, the partition must be unmounted.

     While it is possible to back up an ordinary data partition while it is mounted, it is adviseable to unmount it where possible. The results of attempting to back up a mounted data partition can be unpredicteable.

   # dump -0uf /backup-files/sda1.dump /dev/sda1
   # dump -0uf /backup-files/sda2.dump /dev/sda2
   # dump -0uf /backup-files/sda3.dump /dev/sda3
   

   If you want to do a remote backup, you can use both ssh or configure a non-password login.

   Note

   If using standard redirection, the '-f' option must be passed separately.

   # dump -0u -f - /dev/sda1 | ssh root@remoteserver.example.com dd of=/tmp/sda1.dump