[lbackup-discussion] LBackup general usage questions

henri reply to this message via the mailing list
Thu Jul 12 21:24:45 NZST 2012


These are all good questions. Some basic information on answers are listed inline below. 

Should you require clarification on the points then just let me know.

> (1) Is there a way to set up LBackup so that it backs up using a
> schedule similar to Apple Time Machine? I.e. I am hoping to do
> something like: keep daily backups for the week, weekly backups for
> the past month, monthly backups until some sort of pre-set limit is
> reached (i.e. less than a certain number of total monthly backups, or
> only keep backups from the past year, etc.) I know this may involve
> some fancy cron work, but is there anything I should do on the LBackup
> end? If you have tips on how to set this up in cron that would be
> great, too.

To have Daily / Monthly / Weekly backup sets. It is recommended you operate a separate backup for each schedule you wish to keep and to also have a separate LBackup set. This will consume additional disk space. However, it also means if you have the backup sets on disks which are being removed and taken off site then it is easier to manage them - you just label the disks Monthly / Weekly (etc...).

LBackup keeps a set number of snapshots. This means if there is a problem with the backup taking place the old backups will not be removed until enough good snap shots have been taken of the source directories.

If you schedule a backup to start every day and keep 365 rotations then you will end up with a backup history for a year. One for every single day of the year.

There is also more information in the LBackup mailing list archive : 

This is the specific mail thread related to this question which was posted in the past : 

> (2) My computer needs to be on and awake for scheduled backups to
> occur, right? (I think this is a cron limitation?)

If you use Cron then this is a limitation. LBackup can be scheduled in a number of different ways. Some of these on Mac OS X 10.5.8 include launchd and cron. If you would like a daily backup to take place as soon as possible after a machine switched (catch up) on then you could look at a tool such as Anacron :  http://anacron.sourceforge.net/

Further information on automating LBackup is available from the following URL : http://www.lbackup.org/about#automation

Using LaunchD it is possible to schedule backups to take place when the backup disk is detected as attached to your system. An example script which allows you to easily setup a system which keeps the backup disks unmounted when backups are not taking place is available from the following links : 
 (Mount) http://www.lbackup.org/developer/mounting_attached_backup_devices
 (Un-Mount) http://bit.ly/lbackup-source-example-unmountbackupvolume

If you are using removable media which is transported off site then please note there are some initialization scripts available (link below) which can accomplish tasks such as configuring pre and post-actions which will mounting and un-mount disk images. Disk images may be useful if you are using software encryption. If you require assistance with hardware encryption then please contact Lucid off list and we will discuss your requirements in further detail. Further details on the the initialization script which is able to assist with the setup of mounting and un-mounting (encrypted?) disk images is available from : http://www.lbackup.org/initialization_scripts/initialize_disk_image_pre_and_post_hooks

> (3) Right now the incremental backups are named "Section.n" (sans
> quotes), where n is a number. Is there a way to change this so that
> these backups are named after the dates and times that they were made?
> This will make it very easy for me to find a backup from a specific
> time at a glance.

Changing the name of the Sections is not a simple option at this point in time. However, by enabling the example post-action script (link is provided below) you may easily enable the the dynamic generation and updating of a directory which contains time based links. These links by default are named with the date and time the backup took place and reference the backups with the .n suffix in the parent directory. This may of course be further customized.

Link : http://bit.ly/lbackup-source-example-generatetimebasedbackuplinksdirectory

The example post and pre action scripts may be enabled using a variety of number of ways. The easiest way is to simply copy one from the '/etc/example_backup_config/exmaple-scripts/post-actions' directory within your configuration directory to the 'path_to_your_backup_conf_directory/resources/post-actions' directory within your LBackup configuration directory.

Further information relating to the LBackup pre and post-cation scripts is available from the following links : 

 - http://www.lbackup.org/about#pre_and_post_actions
 - http://www.lbackup.org/pre_and_post_actions
 - http://www.lbackup.org/enable_pre-action_script_for_multiple_backup_configuration_directories

> (4) The LBackup website talks about Mac OS X permissions and ACLs,
> etc. However, in my case I want to strip my files of any OS specific
> metadata, including permissions, etc. Is there a way to achieve this?

At this point in time there is no elegant way to remove all the meta-data and continue to use hard-links for saving backup space. However, to disable the ACL's using the latest build for OS X you could add the following line to the LBackup configuration file : 

disable_acl_preservation="YES" # (If enabled ACL's will not be preserved in the backup)

It is possible that in a future release other options will be supported which will result in less meta-data being backed up. Various other configuration options are able to be viewed from within the LBackup example configuration file : http://bit.ly/lbackup-source-example-backupconfig

> (5) Since LBackup incremental backups use hard links, how will these
> backups (Section.0, Section.1, etc.) look like and behave on a Windows
> system?

At this point in time LBackup is not officially supported with Windows. Although this may change in the future. If you try mounting the backup drive and it works or is not working then please report back. Someone on the mailing list may have been doing something like this with Windows. There have certainly been enquiries relating to windows support for LBackup in the past.

> (6) Looks like LBackup has some SSH capabilities, but the website only
> talks about logging into an SSH server with keys. I have access to a
> SSH server that only allows password authentication, can LBackup
> handle this? My scenario is that I want to backup files on this SSH
> server *to* an external hard drive connected to my computer.

Are you positive that key baed authentication has been disabled?

It is possible to backup even if only password authentication is supported. However, to automate this process securely I would suggest that you ask for the server to have key based authentication enabled.

Simply reply back to the list if you have further questions or require further clarification. Also, your input with the project is of course warmly welcomed. There are many aspects of the project which require improvement and documentation.

Hopefully the information listed above will provide answers to at least some of your questions. 

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