# YaST2 backup Mini-HOWTO

Author: Ladislav Slezak < lslezak@suse.cz>

Changes:

- 2003-02-05: Documentation update
- 2001-12-18: Updated to new Backup module
- 2001-12-05: Initial version

## How to use YaST2 backup module

Note: YaST2 backup module does not replace other backup utilities! The YaST2 backup module is a small, easy-to-use backup program. If you need advanced features, such as incremental backup or network backup, you should use another expert tool.

### How does YaST2 backup work?

YaST2 backup module searches system for files which should be backed up and creates archive from them. The archive contains modified files (which were modified since system installation or package update), files not owned by any package can be optionally added to archive. Critical system disk areas can be added to archive too.

### Backup archive content

Backup archive contains additional information to see when or on which system archive was created, etc.

### Workflow desription

#### Archive setting dialog

At first dialog user can enter some propeties of created archive - file name, comment which will be stored in the archive, etc. Archive type determine type of created archive, which utility will be used for creating archive.

Changed files which belong to one package are stored to one subarchive. All package archives and additional files are archived to one big archive by tar utility. Currently supported archive types:

- tar with tar-gzip subarchives - gzip is used to compress package archives, all files are merged to tar archive
- tar with tar-bzip2 subarchives - bzip2 compression utility is used for package archives - it has better compression ratio, but it is slower
- tar with tar subarchives - no compression at all, only merging files
- tar with star-* subarchives - similar to options above, but subarchives are created by star archiver (ACLs will stored into archive)
- only list file names - This option does not create backup archive, but stores file names to file. This is useful to see which files were changed or to use another archive program.

##### Archive file options

Archive can be splitted to more smaller parts. This is usefule if archive does not fit to one medium. Size of one part can be selected from predefined media or manually selected. Select 'User defined' as volume size to set arbitrary volume size in the text area below.

Predefined floppy disk sizes are for MS-DOS formatted disks, if another file system is used its size have to be manually entered, because it can (and probably will) have different free space for user data.

User defined size can be entered as number of bytes, kilobytes, etc. Units with 'i' in their abbreviation are power of 2, units without 'i' are power of 10 -- 1 kB is 1000 bytes, 1kiB is 1024 bytes, etc. Number can be entered in floating point format, values 1e3 bytes or 0.5 MiB are valid. Tar writes files in 10 kiB blocks (default), so created volumes can be slightly smaller then entered value.

Archive volumes are named <archive_directory><volume_number><archive_basename>. Backup module does not do any check if there is available free space - all volumes have to be stored on the disk and then moved to the floppy disks.

##### Backup options

There are options for selecting which parts of the system will be backed up in this dialog. Checking some options results in more dialogs in the workflow - more information from user is required.

Searching files which do not belong to any package needs lots of memory, because list of all installed files have to be read to it.

Rpm utility is used to search modified files. It allows verifying installed packages by comparing current file attributes with attributes stored in RPM database. Changed files are be detected by different MD5 sum attributes. Computing MD5 sum takes lot of time, so it can be replaced by only comparing size and modification time attributes, but it is less reliable.

##### Excluding

If backing up files not owned by any package is selected, then it can be usefull to set which directories shoud not be backed up (e.g. /tmp)

In Expert settings can be selected file systems instead of directories. Default excluded file system is iso9660 and file systems with "nodev" flag in /proc/filesystems (e.g. nfs, proc, shm, ...). Root directory '/' is searched always, even if its file system is selected.

##### Seaching

Seaching files starts after all unnecessary information is collected. During searching current action or progress is displayed.

##### Files dialog

If user requested to check list of found files then user can select which files from found ones will be backed up.

##### Summary dialog

Here are displayed results of creating archive.

#### Restoring from backup

Files can be restored from backup archive by Yast2 Restore module or manually using tar/star utility.

### Documentation

Other information about YaST2 backup moudule can be found in Backup module specification. If you have another questions or notes contact author please.