NAME

cdbkup - Backup a filesystem to one or more CD-R(W)s

SYNOPSIS

cdbkup 0-9 [ --help ] [ -1, --single ] [ -a, --append ] [ -b, --blank ] [ -c, --compress=TYPE ] [ -e, --exclude=PATH ] [ -h, --host=HOST ] [ -I, --no-iso ] [ -l, --label=NAME ] [ -m, --cross-mp ] [ -r, --recycle ] [ -s, --speed=SPEED ] [ -S, --cdsize=SIZE ] [ -t, --test ] [ -V, --version ] [ -w, --workdir=PATH ] [ -z, --zip-here ] DEVICE DUMPDIR

OPTIONS

0-9: Specify the backup level. See the section on BACKUP LEVELS for more info.
--help: Show usage message and quit.
-1, --single: Burn the last disk in single session mode. Normally, the last disk is burned in multisession mode, allowing for additional data to be appended to the end of it. This option has no effect when used with --append or --recycle, since in these cases, the burn is always done in multisession mode.
-a, --append: Append the backup onto the end of a multisession disk. If the disk is empty, then create the first session. When this option is used, the program runs non-interactively, and the entire backup must fit in the available space on the disk. Make sure to insert the correct disk before running the program.
If this option is used in conjunction with --blank (-b), then the disk is blanked first, and the entire image must fit on the blank CD. See also --recycle.
-b, --blank: Blank all disks before writing. This option may not be used in conjunction with --recycle (-r).
-c, --compress=TYPE: Compress using the specified compression format. Possible options are gz for gzip compression, bz2 for bzip2 compression or none for no compression. The default is gz.
-e, --exclude=PATH: Excludes the specified file or directory from the backup. This option may be specified multiple times.
-h, --host=HOST: Specify the hostname whose filesystem is to be backed up. The CD burner is assumed to be on the localhost. The transfer is done via SSH, so make sure that the remote machine is running an SSH server, and that the local machine has an SSH client installed. If this parameter is not specified, then the local machine is backed up.
-I, --no-iso: This option can only be used in conjunction with both --test and --cdsize. It prevents the backup tarballs from being rolled up into ISO files. See the --cdsize (-S) option for more information.
-l, --label=NAME: Set the backup volume label. If the backup directory is anything other than '/', then this parameter is required. Otherwise, the default volume label is the hostname of the machine being backed up. To generate the filenames for the CD images, cdbkup appends three things to the volume label: the current date, the backup level, and the extension .tar.gz. If the entire image fits on one disk, then this filename is exact. Otherwise, a dot and the disk number are appended to the filename on each disk, after the file extension.
-m, --cross-mp: Cross between filesystems when dumping. By default, cdbkup ignores mount points within the directory tree being backed up. This option causes cdbkup to include these mount points as though they were plain subdirectories.
You can use the --exclude option to explicitly exclude mount points that you don't want, such as /proc and /usb under Linux.
-r, --recycle: Same as --append, except that the disk is blanked first if the data doesn't fit in the available space. If the data is too large to fit even on a blank CD, then the CD is not blanked, but this program returns an error. This option conflicts with --append and --blank.
-s, --speed=SPEED: Set the burn speed. The default is 2.
-S, --cdsize=SIZE: Specify the size of the output media in bytes. Normally, cdbkup attempts to autodetect the size of the disk and uses a default of 650,000,000 bytes if autodetection fails. This option disables autodetection.
Unless --no-iso is specified, SIZE must be large enough to account for both high-level and low-level filesystem overhead. So you should expect any ISO images to be significantly smaller than the given value. If --no-iso is specified then SIZE is the exact maximum filesize.
-t, --test: Do not use the CD-ROM burner. In this mode, the backup proceeds normally, except that the backup file(s) are saved to the current directory instead of being burned onto CD-R(W)s. The output is normally a single tarball. If --cdsize is specified then the output is one or more ISO images. If both --cdsize and --no-iso are specified, then the output is one or more tarballs.
If -t is used, the following options are ignored: -1, -a, -b, -r, -s.
-V, --version: Print the version number and exit.
-w, --workdir=PATH: Set the working directory as specified. The default is /tmp/cdworkdir. Except in the case of remote backups, this directory is automatically excluded from the backup. (See the --exclude option.)
-z, --zip-here: For remote backups, perform compression locally. This has the advantage of decreased CPU load on the remote machine, but the disadvantage of increased network traffic. This option has no effect on local backups.

DESCRIPTION

This manual page documents briefly the cdbkup filesystem backup utility.

cdbkup backs up the filesystem under the specified directory to one or more CD-R(W)s. It can run either interactively, for large backups, or non-interactively, for backups that you expect to fit on a single disk.

In interactive mode, the program asks you to insert CDs at the appropriate times, and offers you the ability to retry in case of errors. In non-interactive mode (using -a or -r), the program expects the target CD to already be in the drive. If an error occurs, the program prints an error message and returns a non-zero status code.

To restore a filesystem, begin with a blank filesystem, and use cdrstr (1) to restore the most recent backups at each level, beginning with the lowest level and increasing.

DEVICES

The device specified on the command line is the SCSI device for the CD-ROM burner. For more information, see the dev= option of cdrecord (1).

BACKUP LEVELS

The range of backup levels (0-9) facilitates a variety of backup strategies. Level 0 always performs a full backup. Higher-level backups usually perform incremental backups, and they only save the changes since the most recent backup of a lower level. So, for instance, monthly backups could be performed at level 0, weekly backups at level 3 and daily backups at level 5. Thus, the daily backups would only save changes since the beginning of the week, and the weekly backups would only save changes since the beginning of the month.

When restoring (using cdrstr (1)), the most recent level 0 backup would have to be restored, followed by the most recent level 3 backup, then by the most recent level 5 backup.

It is recommended to use the --append or --recycle options for daily backups, since many will often fit on the same CD. But for safety, you should alternate between two or more CD-RWs so that, even in the case of failure, you still have a quite recent backup.

Note that you can't put more than one backup performed on the same day of the same filesystem or directory on the same CD-R(W), since the filenames would be identical. In general, it's unusual to perform backups more than once per day, but if you must then use a different CD-R(W).

EXAMPLES

cdbkup 0 -e /tmp -s 4 0,0,0 /: Does a full (level 0) backup of the local root directory, excluding /tmp onto (maybe) multiple CD-Rs, burning at 4-speed. The CD-Rs must already be blank.
cdbkup 0 -b -e /tmp -s 4 0,0,0 /: Same as above, but blanks all disks (which must be CD-RWs) before writing the backup images.
cdbkup 0 -h my.webserver.org -e /tmp 0,0,0 /: Does a full backup of a remote webserver, excluding /tmp onto (maybe) multiple CD-Rs. Compression is performed on the webserver machine in order to save on bandwidth.
cdbkup 0 -h my.webserver.org -z 0,0,0 /: Same as above, except that the /tmp directory is included in the backup, and compression is performed locally in order to avoid loading the webserver's CPU.
cdbkup 5 -a -e /tmp 0,0,0 /: Does a level 5 incremental backup of the local root directory, excluding /tmp onto the remaining space on a multisession CD-R. If the backup doesn't fit, an error is thrown.
cdbkup 5 -r -e /tmp 0,0,0 /: Same as above, but if the backup doesn't fit, blanks the disk, then writes the backup.

AUTHOR

John-Paul Gignac <jp@gignac.org>