pdumpfs
—
A daily backup system similar to Plan9's dumpfs
pdumpfs |
src-dir dest-dir [dest-basename] |
pdumpfs
is a simple daily backup system written in
Ruby
(ruby(1)),
which is similar to Plan9's dumpfs
that preserves
every daily snapshot.
Back up your home directory with pdumpfs
,
and you can retrieve any past day's snapshot of any file.
pdumpfs
constructs each day's snapshot in
the directory named YYYY/MM/DD under the destination
directory. All source files are copied to the snapshot directory for the
first time, and on and after the second time,
pdumpfs
copies only updated or newly created files
and stores unchanged files as hard links to the files of the previous day's
snapshot to save disk space.
The latest version of pdumpfs
is always
available at http://namazu.org/~satoru/pdumpfs/.
To backup your home directory /home/yourname to
/backup, run the following command.
pdumpfs /home/yourname /backup
>/backup/log 2>/backup/error-log
On and after the second day, it is a good idea to invoke the
backup command with
cron(8)
daemon. Adding the following line to your crontab file allows you to back up
your home directory at 5 a.m. everyday.
00 05 * * * pdumpfs /home/yourname
/backup >/backup/log 2>/backup/error-log
If the backup system works well, you can retrieve any given day's
file with a file name like
/backup/2001/02/19/yourname/...
pdumpfs
can only handle normal files, directories,
and symbolic links.
pdumpfs
may not work on systems other than
UNIX because pdumpfs
utilizes hard links.
pdumpfs
is not suited for a directory containing
large files which are updated frequently.
- If more than 31 day absence occurs, incremental backup would not be
performed. So, back up your files on a daily basis.
- With
pdumpfs
, you can safely remove unnecessary
files because the past files can be retrieved at any time. However, you
must not rely too much on pdumpfs
. It may have
serious bugs.
- If the total disk usage increases by 10 MB everyday, about 4 GB disk space
will be consumed every year. It would not matter so much considering the
recent evolution of computer resources.
- Back up your files to a physically separated device.
- On some systems, files can be made immutable.
To make all files in /backup immutable
on Linux, run the following command as root:
chattr -R +i /backup
On 4.4BSD derived systems, run the
following command as root:
chflags -R schg
/backup
These commands will keep you from accidentally removing your
backup files with rm -rf
.
pdumpfs
and the HTML document were written by
Satoru Takabayashi ⟨satoru@namazu.org⟩.
This manual page was translated from the HTML document by
Hiroyuki Shimada ⟨shimaden@din.or.jp⟩,
and reformatted by Akinori MUSHA
⟨knu@iDaemons.org⟩.