`dump`- und `restore`-Kommandos

Übersicht

dump examines files in a filesystem, determines which to back up, and copies those files to a specified disk, tape, or other storage medium. The restore command performs the inverse function of dump.

This utility applies to the following file systems:

• ext2
• ext3
• ext4

Tip

For the xfs file system, use xfsdump.

This is the project's homepage.

Before using this utility, run the following command to install it:

Shell > dnf -y install dump

After installation, two commonly used command tools are available:

• dump
• restore

Das Kommando dump

There are two main uses for this command:

• Perform backup (dump) operations - dump [option(s)] -f <File-Name> <File1> ...
• Review backup (dump) information - dump [-W | -w]

Gängige Optionen sind Folgende:

• -<level> - Backup level. Please replace "level" with any number from 0-9 when used. The number 0 represents full backup, while other numbers represent incremental backup.
• -f <File-Name> - Specify the file name and path after backup.
• -u - After a successful backup, record the backup time in the /etc/dumpdates file. You can use the -u option when the backed-up object is an independent partition. However, you cannot use the -u option when the backup object is a non-partitioned directory.
• -v - Display the processing details during the backup process.
• -W - An option for viewing dump information.
• -z[LEVEL] - Adjust the compression level using the zlib library, with a default compression level of 2. For example, you can compress the backup file to .gz format. The adjustable range of compression level is 1-9.
• -j[LEVEL] - Adjust the compression level using the bzlib library, with a default compression level of 2. For example, you can compress the backup file to .bz2 format. The adjustable range of compression level is 1-9.

dump-Beispiel

1. Perform a Full Backup of the root partition:

   Shell > dump -0u -j3 -f /tmp/root-20241208.bak.bz2 /
   DUMP: Date of this level 0 dump: Sun Dec  8 19:04:39 2024
   DUMP: Dumping /dev/nvme0n1p2 (/) to /tmp/root-20241208.bak.bz2
   DUMP: Label: none
   DUMP: Writing 10 Kilobyte records
   DUMP: Compressing output at transformation level 3 (bzlib)
   DUMP: mapping (Pass I) [regular files]
   DUMP: mapping (Pass II) [directories]
   DUMP: estimated 14693111 blocks.
   DUMP: Volume 1 started with block 1 at: Sun Dec  8 19:04:41 2024
   DUMP: dumping (Pass III) [directories]
   DUMP: dumping (Pass IV) [regular files]
   DUMP: 20.69% done at 10133 kB/s, finished in 0:19
   DUMP: 43.74% done at 10712 kB/s, finished in 0:12
   DUMP: 70.91% done at 11575 kB/s, finished in 0:06
   DUMP: 93.23% done at 11415 kB/s, finished in 0:01
   DUMP: Closing /tmp/root-20241208.bak.bz2
   DUMP: Volume 1 completed at: Sun Dec  8 19:26:08 2024
   DUMP: Volume 1 took 0:21:27
   DUMP: Volume 1 transfer rate: 5133 kB/s
   DUMP: Volume 1 14722930kB uncompressed, 6607183kB compressed, 2.229:1
   DUMP: 14722930 blocks (14377.86MB) on 1 volume(s)
   DUMP: finished in 1287 seconds, throughput 11439 kBytes/sec
   DUMP: Date of this level 0 dump: Sun Dec  8 19:04:39 2024
   DUMP: Date this dump completed:  Sun Dec  8 19:26:08 2024
   DUMP: Average transfer rate: 5133 kB/s
   DUMP: Wrote 14722930kB uncompressed, 6607183kB compressed, 2.229:1
   DUMP: DUMP IS DONE
   
   Shell > ls -lh /tmp/root-20241208.bak.bz2
   -rw-r--r-- 1 root root 6.4G Dec  8 19:26 /tmp/root-20241208.bak.bz2
   

2. After successful dumping, check the relevant information:

   Shell > cat /etc/dumpdates
   /dev/nvme0n1p2 0 Sun Dec  8 19:04:39 2024 +0800
   
   Shell > dump -W
   Last dump(s) done (Dump '>' file systems):
   /dev/nvme0n1p2        (     /) Last dump: Level 0, Date Sun Dec  8 19:04:39 2024
   

3. Implement Incremental Backup on the basis of Full Backup:

   Shell > echo "jack" >> /tmp/tmpfile.txt
   
   Shell > dump -1u -j4 -f /tmp/root-20241208-LV1.bak.bz2 /
   DUMP: Date of this level 1 dump: Sun Dec  8 19:38:51 2024
   DUMP: Date of last level 0 dump: Sun Dec  8 19:04:39 2024
   DUMP: Dumping /dev/nvme0n1p2 (/) to /tmp/root-20241208-LV1.bak.bz2
   DUMP: Label: none
   DUMP: Writing 10 Kilobyte records
   DUMP: Compressing output at transformation level 4 (bzlib)
   DUMP: mapping (Pass I) [regular files]
   DUMP: mapping (Pass II) [directories]
   DUMP: estimated 6620898 blocks.
   DUMP: Volume 1 started with block 1 at: Sun Dec  8 19:38:58 2024
   DUMP: dumping (Pass III) [directories]
   DUMP: dumping (Pass IV) [regular files]
   DUMP: 38.13% done at 8415 kB/s, finished in 0:08
   DUMP: 75.30% done at 8309 kB/s, finished in 0:03
   DUMP: Closing /tmp/root-20241208-LV1.bak.bz2
   DUMP: Volume 1 completed at: Sun Dec  8 19:52:03 2024
   DUMP: Volume 1 took 0:13:05
   DUMP: Volume 1 transfer rate: 8408 kB/s
   DUMP: Volume 1 6620910kB uncompressed, 6600592kB compressed, 1.004:1
   DUMP: 6620910 blocks (6465.73MB) on 1 volume(s)
   DUMP: finished in 785 seconds, throughput 8434 kBytes/sec
   DUMP: Date of this level 1 dump: Sun Dec  8 19:38:51 2024
   DUMP: Date this dump completed:  Sun Dec  8 19:52:03 2024
   DUMP: Average transfer rate: 8408 kB/s
   DUMP: Wrote 6620910kB uncompressed, 6600592kB compressed, 1.004:1
   DUMP: DUMP IS DONE
   
   Shell > cat /etc/dumpdates
   /dev/nvme0n1p2 0 Sun Dec  8 19:04:39 2024 +0800
   /dev/nvme0n1p2 1 Sun Dec  8 19:38:51 2024 +0800
   
   Shell > dump -W
   Last dump(s) done (Dump '>' file systems):
   /dev/nvme0n1p2        (     /) Last dump: Level 1, Date Sun Dec  8 19:38:51 2024
   

4. For non-partitioned directory, you can only use the Full Backup (-0) option, not the -u option:

   Shell > dump -0uj -f /tmp/etc-full-20241208.bak.bz2 /etc/
   DUMP: You can't update the dumpdates file when dumping a subdirectory
   DUMP: The ENTIRE dump is aborted.
   
   Shell > dump -0j -f /tmp/etc-full-20241208.bak.bz2 /etc/
   DUMP: Date of this level 0 dump: Sun Dec  8 20:00:38 2024
   DUMP: Dumping /dev/nvme0n1p2 (/ (dir etc)) to /tmp/etc-full-20241208.bak.bz2
   DUMP: Label: none
   DUMP: Writing 10 Kilobyte records
   DUMP: Compressing output at transformation level 2 (bzlib)
   DUMP: mapping (Pass I) [regular files]
   DUMP: mapping (Pass II) [directories]
   DUMP: estimated 28204 blocks.
   DUMP: Volume 1 started with block 1 at: Sun Dec  8 20:00:38 2024
   DUMP: dumping (Pass III) [directories]
   DUMP: dumping (Pass IV) [regular files]
   DUMP: Closing /tmp/etc-full-20241208.bak.bz2
   DUMP: Volume 1 completed at: Sun Dec  8 20:00:40 2024
   DUMP: Volume 1 took 0:00:02
   DUMP: Volume 1 transfer rate: 3751 kB/s
   DUMP: Volume 1 29090kB uncompressed, 7503kB compressed, 3.878:1
   DUMP: 29090 blocks (28.41MB) on 1 volume(s)
   DUMP: finished in 2 seconds, throughput 14545 kBytes/sec
   DUMP: Date of this level 0 dump: Sun Dec  8 20:00:38 2024
   DUMP: Date this dump completed:  Sun Dec  8 20:00:40 2024
   DUMP: Average transfer rate: 3751 kB/s
   DUMP: Wrote 29090kB uncompressed, 7503kB compressed, 3.878:1
   DUMP: DUMP IS DONE
   

Performing an incremental backup of the /etc/ directory will result in an error:

```bash
Shell > dump -1j -f /tmp/etc-incr-20241208.bak.bz2 /etc/
DUMP: Only level 0 dumps are allowed on a subdirectory
DUMP: The ENTIRE dump is aborted.
```

restore-Kommando

The usage of this command is - restore <mode(flag)> [option(s)] -f <Dump-File>

The mode (flag) can be one of the following:

• -C - Compare-Modus. Restore reads the backup and compares its contents with files on the disk. Es wird hauptsächlich zum Vergleichen nach der Durchführung einer Sicherung auf einer Partition verwendet. In diesem Modus vergleicht restore nur Änderungen basierend auf den Originaldaten. If there is new data on the disk, you cannot compare or detect it.
• -i - Interactive Mode. This mode allows interactive restoration of files from a dump.
• -t - List-Mode. List what data is in the backup file.
• -r - Restore (rebuild) mode. If it is a "Full Backup + Incremental Backup" method, restoring data will occur chronologically.
• -x - Extraktion-Modus. Extract some or all files from the backup file.

Example of using restore

1. Restore data from /tmp/etc-full-20241208.bak.bz2 :

   Shell > mkdir /tmp/data/
   
   Shell > restore -t -f /tmp/etc-full-20241208.bak.bz2
   
   Shell > cd /tmp/data/ ; restore -r -f /tmp/etc-full-20241208.bak.bz2
   
   Shell > ls -l /tmp/data/
   total 4992
   drwxr-xr-x. 90 root root    4096 Dec  8 17:13 etc
   -rw-------   1 root root 5107632 Dec  8 20:39 restoresymtable
   

As you can see, a file named restoresymtable shows up after a successful restore. Diese Datei ist wichtig. It is for incremental backup system restore operations.

1. Process backup files in Interactive mode:

   Shell > restore -i -f /tmp/etc-full-20241208.bak.bz2
   Dump tape is compressed.
   
   restore > ?
   

You can type ? to view the available interactive commands in this mode.

Author: tianci li

Contributors: Steven Spencer