Examples¶
Let’s make a backup of configuration files of all users except the user “foo”. Let’s assume that our system has unix-like style of home directories (directory “/home” contains directories of all users; configuration files begins with dot). Name of this backup will be “user-configs”.
Configuring the Archive Example¶
First, we need to create the file “user-configs.aa” under the “~/.config/aa/archive_specs/” directory - this is the
archive specification file. The file doesn’t need to have the same name as the backup. If it does however, the
option name can be left out (in this example we specified it anyway, even it is not needed).
In the path variable we specify the archive root which is the the base directory which content we want to
backup.
Variables include-files and exclude-files contains list of files and directories that we want to be included or
excluded respectively. In this example we specify */.* pattern because we want to include home directories of all
users (such as /home/bob, /home/joe, etc.), what the first * is for. And from within those user home
directories we want to include everything that begins with . (for example /home/bob/.bashrc), what the .*
pattern is for. Paths specified in these variables are relative to path.
Although, yet we do not want to include all user home directories as we specified in include-files. Those
directories that should not be included we put in exclude-files (“foo” in this example, which makes /home/foo
excluded). If we would not want to exclude any file then the corresponding variable would be specified as
exclude-files =.
Content of the “user-configs.aa” file:
# ------ begin of user-configs.aa ------
# AutoArchive's archive specification file for users configuration files
[Content]
name = user-configs
path = /home
include-files = */.*
exclude-files = foo
[Archive]
dest-dir = /mnt/backup
# ------ end of user-configs.aa ------
Backup Creation Example¶
Once we configured the archive we can create the backup easily with command:
aa user-configs
and in the “/mnt/backup” directory the file “user-configs.tar.gz” will be created.
Given the “user-configs.aa” example file above, the command:
aa -i user-configs
will create level 0 incremental backup – “user-configs.tar.gz” which is essentially the same as a non-incremental backup. Another execution of the same command will create level 1 backup named “user-configs.1.tar.gz” which contains only a differences from level 0. Each subsequent call will create a next level which will contain only a differences from previous.
In order to restart to level 0 again, thus create a fresh full backup, the following command can be used:
aa -i -l 0 user-configs
Note that you should remove all previously created “user-configs” backups with level higher than 0
because they are no longer valid in regards to the newly created level 0 backup. You may pass
--remove-obsolete-backups option to the command above and they will be removed automatically.
Backup Keeping¶
We assume that all previously created backups were removed in order to demonstrate the backup keeping.
First we create a standard backup:
aa user-configs
This creates “user-configs.tar.gz” backup. Some days later let’s say, we want to create the same backup again.
However we do not want to overwrite the original one. The option -k can be used to keep the original backup:
aa -k user-configs
This will rename the original backup to “user-configs.aa.tar.gz” and create the new one “user-configs.tar.gz”.
If we create the same backup for the third time (still using the -k) option, “user-configs.aa.tar.gz” will be
removed, “user-configs.tar.gz” will be renamed to “user-configs.aa.tar.gz” and the new “user-configs.tar.gz” will be
created. So AutoArchive by default keeps single old backup when -k options is specified. To keep more, e.g. four
backups we would specify --number-of-old-backups=4 alongside with -k.
Incremental backups can be kept as well. Again, we assume that all previously created backups were removed. Let’s create a few levels of incremental “user-configs” archive:
aa -i -l 0 user-configs
aa -i user-configs
aa -i user-configs
aa -i user-configs
This will create following files:
user-configs.tar.gz
user-configs.1.tar.gz
user-configs.2.tar.gz
user-configs.3.tar.gz
Then we (manually) restart to level 2 while asking to keep old backups:
aa -i -l 2 -k user-configs
After this command following files will be present:
user-configs.tar.gz
user-configs.1.tar.gz
user-configs.2.tar.gz
user-configs.2.aa.tar.gz
user-configs.3.aa.tar.gz
Let’s explain what happened. The original file “user-configs.2.tar.gz” was going to be overwritten therefore it was renamed to “user-configs.2.aa.tar.gz”. As all backup levels higher than the renamed one depends on it they have to be renamed as well. In this example “user-configs.3.tar.gz” depends on “user-configs.2.tar.gz” therefore it was renamed to “user-configs.3.aa.tar.gz”. Finally the new increment “user-configs.2.tar.gz” was created.
Listing Archives Example¶
Our “user-configs” archive can be listed by following command:
aa --list
Which results to the following output:
user-configs /home /mnt/backups [0]/[1]/[10]
If we pass --verbose option then it shows:
Name: user-configs
Root: /home
Archiver type: targz
Destination directory: /mnt/backups
Current backup level/next/max.: [0]/[1]/[10]
Target backup level for non-full restart: [1]
Upcoming restart reason: [No restart scheduled for the next backup.]
Restart count/max.: [-]/[-]
Days since last restart/max.: [-]/[-]
Days since last full restart/max.: [-]/[-]
The archive Name is “user-configs” as configured with the name variable in the
Configuring the Archive Example section. Root corresponds to the value configured with the path variable.
Archiver type is “targz” which is the default. Destination directory “/mnt/backup” is configured with dest-dir
variable. Current backup level/next/max. shows [0]/[1]/[10] because in the section Backup Creation Example we
have created an incremental backup of level 0, so current level is 0. Next level is 1 (restarting is not enabled).
Both the current and the next levels are enclosed in square brackets because incremental archiving is not enabled (it
was enabled only temporarily with the -i option). Finally, the maximal backup level is 10 as it is the default.
It is also shown in square brackets because restarting is not enabled; this also applies for all following values.
Since no max-restart-level-size is specified the Target backup level for non-full restart is and always be 1.
Obviously, no restart is scheduled as the Upcoming restart reason value is showing. Since no restart ever occurred
and no value is specified for the rest of restarting options the values Restart count/max., Days since last
restart/max. and Days since last full restart/max. shows only dashes.
Cleaning Orphaned Information Example¶
If we remove the “user-configs.aa” archive specification file then the --list will still be showing the archive
with its name enclosed in square brackets (it becomes the orphaned archive):
[user-configs] ? . [0]/[?]/[10]
This is because some information is still stored in the AutoArchive’s configuration directory. It is the snapshot file
created by tar when incremental backup was created. There may be more information left behind if
restarting would be enabled. All of this orphaned information can be deleted with the --purge command:
aa --purge user-configs
or:
aa --purge --all
which would remove all orphaned archives.
Backup Restoration Example¶
Restoring Non-Incremental Backup¶
Let’s say we have created simple (non-incremental) backup as in the Backup Creation Example. Thus we have a file called “user-configs.tar.gz” in the “/mnt/backup” directory. As the AutoArchive does not handle restoration we will use standard GNU tar archiver.
To restore the backup to its original destination and thus replace all existing files with the ones from the backup we can use following command:
tar -xf /mnt/backup/user-configs.tar.gz -C /home
The value of the -C option (/home) is the same as the value of path variable in the “user-configs.aa”. The
-C option can be left out if the destination is the current working directory (in other words you did “cd /home”
earlier).
Of course the backup can be restored to any arbitrary location by replacing “/home” with some other path in the command above. This may be more safe and convenient as it does not replaces original files. The extracted backup files can be reviewed and copied to the original destination afterwards. You may also use a graphical file manager or an archive manager to browse content of the backup interactively.
Restoring Incremental Backup¶
Suppose we have several increments of the “user-configs” archive in the /mnt/backup directory. The content of the directory is following:
$ ls -1 /mnt/backup
-rw-r--r-- 1 root root 10M Apr 20 17:07 user-configs.tar.gz
-rw-r--r-- 1 root root 1M May 11 12:21 user-configs.1.tar.gz
-rw-r--r-- 1 root root 1.5M Jun 26 16:43 user-configs.2.tar.gz
Which means we have backup level 0, 1 and 2. To restore entire backup to the latest possible date (in this case Jun 26) we have to restore all backup levels. Similarly to the previous example the following series of commands will restore the backup to the original location replacing the original files there:
tar -xf /mnt/backup/user-configs.tar.gz -G -C /home
tar -xf /mnt/backup/user-configs.1.tar.gz -G -C /home
tar -xf /mnt/backup/user-configs.2.tar.gz -G -C /home
As in the previous example the “-C /home” can be left out (backup will be restored to the current directory) or “/home” replaced with some other path (backup will be restored to that path).
Referring To External Archive Specification Example¶
In this example we want to configure archive for “/data” directory backups. There will be two locations where backups are stored. One is a large capacity NAS mounted at “/mnt/nas”, the other is a smaller external disk mounted at “/mnt/backup_disk”.
Below is content of two archive specification files for this use case. The first one
configures archive “data-nas” for NAS storage destination. Second file configures archive “data-disk” for
external disk location. It is taking all values except dest-dir from the “data-nas.aa” file via external
references. Additionally it excludes “videos” directory so that backup will fit to disk.
# ------ begin of data-nas.aa ------
[Content]
path = /
include-files = data-nas
exclude-files =
[Archive]
dest-dir = /mnt/nas
# ------ end of data-nas.aa ------
# ------ begin of data-disk.aa ------
[External]
data-nas
[Content]
path = @(data-nas.path)
include-files = @(data-nas.include-files)
exclude-files = @(data-nas.exclude-files) videos
[Archive]
dest-dir = /mnt/backup_disk
# ------ end of data-disk.aa ------
Specifying path to the external file¶
Would the “data-nas.aa” file in previous example be in a different directory than archive specifications directory its path had to be specified:
# ------ begin of data-disk.aa ------
[External]
data-nas = /path/to/data-nas.aa
[Content]
# ...
# ------ end of data-disk.aa ------