openSolaris 2008 - Backing Up a File System - System Administration Guide: Devices and File Systems

Backing Up a File System

The following are general guidelines for performing backups:

Use single-user mode or unmount the file system, unless you are creating a snapshot of a file system. For information about UFS snapshots, see Chapter 26, Using UFS Snapshots (Tasks).
Be aware that backing up file systems when directory-level operations (such as creating, removing, and renaming files) and file-level activity are occurring simultaneously means that some data will not be included in the backup.
You can run the ufsdump command from a single system and remotely back up groups of systems across the network through remote shell or remote login. In addition, you can direct the output to the system on which the tape device is located. Typically, the tape device is located on the system from which you run the ufsdump command, but it does not have to be.
Another way to back up files to a remote device is to pipe the output from the ufsdump command to the dd command. For information about using the dd command, see Chapter 29, Copying UFS Files and File Systems (Tasks).
If you are doing remote backups across the network, the system with the tape device must have entries in its /.rhosts file for each client that will be using the device. Also, the system that initiates the backup must be included in the /.rhosts file on each system that it will back up.

How to Back Up a File System to Tape

The following are general steps for backing up file systems by using the ufsdump command. The examples show specific uses of options and arguments.

Become superuser or assume an equivalent role.
Bring the system to run level S (single-user mode).
For example:
```
# shutdown -g30 -y
```
(Optional) Check the file system for consistency.
For example:
```
# fsck -m /dev/rdsk/c0t0d0s7
```
The fsck -m command checks for the consistency of file systems. For example, power failures can leave files in an inconsistent state. For more information on the fsck command, see Chapter 22, Checking UFS File System Consistency (Tasks).
If you need to back up file systems to a remote tape drive, follow these steps:
1. On the system to which the tape drive is attached (the tape server), add the following entry to its /.rhosts file:
```
host root
```
  The host entry specifies the name of the system on which you will run the ufsdump command to perform the backup.
2. On the tape server, verify that the host added to the /.rhosts file is accessible through the name service.
Identify the device name of the tape drive.
The default tape drive is the /dev/rmt/0 device.
Insert a tape that is write-enabled into the tape drive.
Back up file systems.
```
# ufsdump options arguments filenames
```
You can back up file systems or directories, or files within file systems. For information on backing up individual files, see tar(1) or cpio(1).
The following examples show how to use the most common ufsdump options and arguments:
For other ufsdump options and arguments, see Chapter 28, UFS Backup and Restore Commands (Reference).
If prompted, remove the tape and insert the next tape volume.
Label each tape with the volume number, dump level, date, system name, disk slice, and file system.
Bring the system back to run level 3 by pressing Control-D.
Verify that the backup was successful.
```
# ufsrestore tf device-name
```

Example 25-3 Performing a Full Backup of root (/)

The following example shows how to do a full backup of the root (/) file system. The system in this example is brought to single-user mode before the backup. The following ufsdump options are included:

0 specifies a 0 level dump (or a full backup).
u specifies that the /etc/dumpdates file is updated with the date of this backup.
c identifies a cartridge tape device.
f /dev/rmt/0 identifies the tape device.
/ is the file system being backed up.

For example:

# init 0
ok boot -s
# ufsdump 0ucf /dev/rmt/0 /
  DUMP: Date of this level 0 dump: Wed Jul 28 16:13:52 2004
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rdsk/c0t0d0s0 (starbug:/) to /dev/rmt/0.
  DUMP: Mapping (Pass I) [regular files]
  DUMP: Mapping (Pass II) [directories]
  DUMP: Writing 63 Kilobyte records
  DUMP: Estimated 363468 blocks (177.47MB).
  DUMP: Dumping (Pass III) [directories]
  DUMP: Dumping (Pass IV) [regular files]
  DUMP: Tape rewinding
  DUMP: 369934 blocks (180.63MB) on 1 volume at 432 KB/sec
  DUMP: DUMP IS DONE
  DUMP: Level 0 dump on Wed Jul 28 16:13:52 2004
  # ufsrestore tf /dev/rmt/0
         2      .
         3      ./lost+found
         4      ./usr
         5      ./export
         6      ./export/home
         7      ./var
         8      ./var/sadm
         9      ./var/sadm/install
        10      ./var/sadm/install/admin
       823      ./var/sadm/install/admin/default
        11      ./var/sadm/install/logs
       697      ./var/sadm/install/logs/SUNWmpatchmgr
       905      ./var/sadm/install/logs/Additional_Software_install...
       906      ./var/sadm/install/logs/Additional_Software_install...
        13      ./var/sadm/install/.lockfile
        14      ./var/sadm/install/install.db
       824      ./var/sadm/install/special_contents
       838      ./var/sadm/install/contents
                .
                .
                .
  # (Press Control-D to bring system to run level 3)

Example 25-4 Performing an Incremental Backup of root (/)

The following example shows how to do an incremental backup of the root (/) file system in single-user mode. The following ufsdump options are included:

9 specifies a 9 level dump (or an incremental backup).
u specifies that the /etc/dumpdates file is updated with the date of this backup.
c identifies a cartridge tape device.
f /dev/rmt/0 identifies the tape device.
/ is the file system being backed up.

# init 0
ok boot -s
# ufsdump 9ucf /dev/rmt/0 /
 DUMP: Date of this level 9 dump: Wed Jul 28 14:26:50 2004
 DUMP: Date of last level 0 dump: Wed Jul 28 11:15:41 2004
 DUMP: Dumping /dev/rdsk/c0t0d0s0 (starbug:/) to /dev/rmt/0.
 DUMP: Mapping (Pass I) [regular files]
 DUMP: Mapping (Pass II) [directories]
 DUMP: Writing 63 Kilobyte records
 DUMP: Estimated 335844 blocks (163.99MB).
 DUMP: Dumping (Pass III) [directories]
 DUMP: Dumping (Pass IV) [regular files]
 DUMP: 335410 blocks (163.77MB) on 1 volume at 893 KB/sec
 DUMP: DUMP IS DONE
 DUMP: Level 9 dump on Wed Jul 28 14:30:50 2004
 # ufsrestore tf /dev/rmt/0
         2      .
         3      ./lost+found
      5696      ./usr
     11392      ./var
     17088      ./export
     22784      ./export/home
     28480      ./opt
      5697      ./etc
     11393      ./etc/default
     11394      ./etc/default/sys-suspend
     11429      ./etc/default/cron
     11430      ./etc/default/devfsadm
     11431      ./etc/default/dhcpagent
     11432      ./etc/default/fs
     11433      ./etc/default/inetinit
     11434      ./etc/default/kbd
     11435      ./etc/default/nfslogd
     11436      ./etc/default/passwd
     11437      ./etc/default/tar
                .
                .
                .

Example 25-5 Performing a Full Backup of a Home Directory

The following example shows how to do a full backup of the /export/home/kryten home directory. The following ufsdump options are included:

0 specifies that this is a 0 level dump (or a full backup).
u specifies that the /etc/dumpdates file is updated with the date of this backup.
c identifies a cartridge tape device.
f /dev/rmt/0 identifies the tape device.
/export/home/kryten is the directory being backed up.

# ufsdump 0ucf /dev/rmt/0 /export/home/kryten
  DUMP: Date of this level 0 dump: Wed Jul 28 15:02:48 2004
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rdsk/c0t0d0s7 (starbug:/export/home) to /dev/rmt/0.
  DUMP: Mapping (Pass I) [regular files]
  DUMP: Mapping (Pass II) [directories]
  DUMP: Writing 63 Kilobyte records
  DUMP: Estimated 2412 blocks (1.18MB).
  DUMP: Dumping (Pass III) [directories]
  DUMP: Dumping (Pass IV) [regular files]
  DUMP: 2392 blocks (1.17MB) on 1 volume at 4241 KB/sec
  DUMP: DUMP IS DONE
# ufsrestore tf /dev/rmt/0
       232      ./kryten
       233      ./kryten/filea
       234      ./kryten/fileb
       235      ./kryten/filec
       236      ./kryten/letters
       237      ./kryten/letters/letter1
       238      ./kryten/letters/letter2
       239      ./kryten/letters/letter3
       240      ./kryten/reports
       241      ./kryten/reports/reportA
       242      ./kryten/reports/reportB
       243      ./kryten/reports/reportC
#

Example 25-6 Performing a Full Backup to a Remote System ( Data to System)

The following example shows how to do a full backup of a local /export/home file system on a system (mars) to a tape device on a remote system (earth) in single-user mode. The following ufsdump options are included:

0 specifies a 0 level dump (or a full backup).
u specifies that the /etc/dumpdates file is updated with the date of this backup.
c identifies a cartridge tape device.
f earth:/dev/rmt/0 identifies the remote system name and tape device.
/export/home is the file system being backed up.

# ufsdump 0ucf earth:/dev/rmt/0 /export/home
  DUMP: Date of this level 0 dump: Wed Jul 28 15:52:59 2004
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rdsk/c0t0d0s7 (mars:/export/home) to earth:/dev/rmt/0.
  DUMP: Mapping (Pass I) [regular files]
  DUMP: Mapping (Pass II) [directories]
  DUMP: Writing 63 Kilobyte records
  DUMP: Estimated 8282 blocks (4.04MB).
  DUMP: Dumping (Pass III) [directories]
  DUMP: Dumping (Pass IV) [regular files]
  DUMP: Tape rewinding
  DUMP: 8188 blocks (4.00MB) on 1 volume at 67 KB/sec
  DUMP: DUMP IS DONE
  DUMP: Level 0 dump on Wed Jul 28 15:52:59 2004
# ufsrestore tf earth:/dev/rmt/0
         2      .
         3      ./lost+found
         4      ./kryten
         5      ./kryten/filea
         6      ./kryten/fileb
         7      ./kryten/filec
         8      ./kryten/letters
         9      ./kryten/letters/letter1
        10      ./kryten/letters/letter2
        11      ./kryten/letters/letter3
        12      ./kryten/reports
.
.
.
 #