by Gundolf Kiefer, 2001-2022
backup2l is a lightweight command line tool for generating, maintaining and restoring backups on a mountable file system (e. g. hard disk). The main design goals are are low maintenance effort, efficiency, transparency and robustness. In a default installation, backups are created autonomously by a cron script.
backup2l supports hierarchical differential backups with a user-specified number of levels and backups per level. With this scheme, the total number of archives that have to be stored only increases logarithmically with the number of differential backups since the last full backup. Hence, small incremental backups can be generated at short intervals while time- and space-consuming full backups are only sparsely needed.
The restore function allows to easily restore the state of the file system or arbitrary directories/files of previous points in time. The ownership and permission attributes of files and directories are correctly restored.
An open driver architecture allows to use virtually any archiving program as a backend. Built-in drivers support .tar.gz, .tar.bz2, or .afioz files. Further user-defined drivers can be added as described in the supplied sample configuration file ‘first-time.conf’.
An integrated split-and-collect function allows to comfortably transfer all or selected archives to a set of CDs or other removable media.
All control files are stored together with the archives on the backup device, and their contents are mostly self-explaining. Hence, in the case of an emergency, a user does not only have to rely on the restore functionality of backup2l, but can - if necessary - browse the files and extract archives manually.
For deciding whether a file is new or modified, backup2l looks at its name, modification time, size, ownership and permissions. Unlike other backup tools, the i-node is not considered in order to avoid problems with non-Unix file systems like FAT32.
a) Generating a backup: mail received from cron daemon
The monitored area covers 26803 (=23733+3053) files and directories and over 2.2 GB of data. Look at the time stamps!
backup2l v1.6 by Gundolf Kiefer
Wed Nov 6 07:58:00 CET 2019
Mounting /disk2...
Running pre-backup procedure...
writing dpkg selections to /root/getselections.log...
Removing old backups...
Preparing differential level-3 backup <all.1104> based on <all.1103>...
657 / 23745 file(s), 94 / 3058 dir(s), 63945 / 2332639 KB (uncompressed)
skipping: 498 file(s), 14 dir(s), 3144527 KB (uncompressed)
Creating archive...
Checking TOC of tar file (< real file, > archive entry)...
Creating check file for <all.1104>...
Wed Nov 6 07:58:41 CET 2019
Summary
=======
Archive Date | Size (KB) | Skipped Files+Dirs | New Obs. | Errors
------------------------------------------------------------------------------
all.1 2019-07-15 | 1475248 | 620 17795 |17795 0 | 45
all.101 2019-07-27 | 235720 | 617 17002 | 812 1605 | 2
all.102 2019-08-19 | 210648 | 626 23446 | 7077 633 | 1
all.103 2019-08-30 | 125396 | 670 23796 | 1963 1613 | 0
all.104 2019-09-07 | 203880 | 669 25597 | 5353 3552 | 1
all.105 2019-09-20 | 87076 | 409 24333 | 2192 3456 | 6
all.106 2019-10-01 | 88492 | 409 27611 | 4591 1313 | 1
all.107 2019-10-12 | 67624 | 409 26589 | 1194 2216 | 0
all.108 2019-10-21 | 111580 | 506 26553 | 1351 1387 | 0
all.1081 2019-10-21 | 948 | 506 26554 | 70 69 | 0
all.1082 2019-10-22 | 164 | 506 26554 | 90 90 | 0
all.1083 2019-10-23 | 46680 | 506 27814 | 1465 205 | 0
all.1084 2019-10-24 | 29672 | 506 28578 | 1111 347 | 0
all.1085 2019-10-25 | 28272 | 506 26869 | 282 1991 | 0
all.1086 2019-10-26 | 45000 | 506 26866 | 314 317 | 0
all.1087 2019-10-27 | 33136 | 506 27162 | 610 314 | 0
all.1088 2019-10-28 | 12280 | 506 27645 | 673 190 | 0
all.11 2019-10-29 | 822056 | 506 27725 |13582 3652 | 8
all.1101 2019-10-30 | 20888 | 506 23707 | 858 4876 | 0
all.1102 2019-10-31 | 11336 | 512 26807 | 3372 272 | 0
all.1103 2019-11-05 | 312 | 512 26786 | 173 194 | 0
all.1104 2019-11-06 | 49592 | 512 26803 | 751 734 | 0
Filesystem Size Used Avail Use% Mounted on
/dev/hde1 5.8G 3.5G 2.3G 61% /disk2
Unmounting /disk2...b) Restoring directory from snapshot into working directory
Restoring the directory /home/home/gundolf/prog/ from snapshot <all.1102> into the current working directory:
lilienthal:/scratch# backup2l -t 1102 -r /home/gundolf/prog/
backup2l v1.6 by Gundolf Kiefer
Mounting /disk2...
Active files in <all.1102>: 246
found in all.1102: 119 ( 127 left)
found in all.1101: 7 ( 120 left)
found in all.11: 120 ( 0 left)
Restoring 35 directories...
Restoring files...
all.11: 120 file(s)
all.1101: 7 file(s)
all.1102: 119 file(s)
Unmounting /disk2...
lilienthal:/scratch#