Re: Announcing xorriso-0.2.6
> Currently I backup a source directory,
> then detect the files changed since the last update, use a small
> script to generate a file suitable for mkisofs with -graft-points,
> and update only those files.
If you want to stay near to mkisofs -graft-points
semantics, then use
and the insertion option
-add ... --
The delimiter "--" can be omitted if after -add
there are only pathspecs and no other options.
The final option -commit can be omitted at the end
of the program if one does not want to eject the media.
xorriso ...other.options... -pathspecs on -add \
You can get even nearer to mkisofs behavior by
the emulation option
-as mkisofs ...mkisofs.options.and.pathspecs... --
Available mkisofs options are
-R (always on), -J, -o, -M, -C, -path-list, -m,
-exclude-list, -f, -print-size, -pad, -no-pad, -V, -v, -version,
Before option -as and after the delimiter "--" you may use
normal xorriso options.
So you may address the drive for reading and writing by
-dev /dev/sr0 -as mkisofs ...no.-o.here...
If no drive was selected then the write target is stdout.
If you select a write target by -o then this will be handled
as file object ("stdio:" pseudo-drive) and not as optical drive.
The delimiter may be omitted if no original xorriso
options shall follow the mkisofs options.
I use xorriso as "mkisofs" and as "cdrecord" within
my own backup tool:
xorriso -as mkisofs ... | checksummer | xorriso -as cdrecord ...
> needs no fancy hiding or such,
-notleaf is not mandatory at all.
It is in the example to demonstrate its cooperation
with incremental backup command -update_r.
Your script does its own decisions (like my backup tool)
and thus is well served by -add or -map or -cp_r or
by -as mkisofs.
Your script may delete outdated files if desired.
I believe it serves the usability of a backup if it
only restores valid files by default.
The deleted files are not gone but still available
by mounting older sessions.
> I just want to (a) not lose data and
I advise to use media alternatingly in order to
avoid the risk of losing the most recent backup
by any accident.
If backups are important for a long time then they
should be checkread in regular intervals.
xorriso offers option -check_media based on the drive's
error detection. This is the same error check that
is done by the block device driver but the latter tends
to ignore follow-up errors after the first bad spot.
-check_media is able to make repeated, cummulative
data rescue attempts.
> (b) be able to roll back to any point in time by mounting a session.
If drive and/or operating system are inapt to find
the most recent session or if you want to mount older
sessions on non-CD you will have to learn the sbsector=
argument for mount from xorriso -toc.
xorriso gives an own guarantee of data format readability
by its own options for image loading and file extraction.
See: -load, -osirrox and -extract.
It is also possible to base an update session on a
session that is older than the most recent one.
This helps if the youngest session produces
read errors already in the directory tree of the image.
(I have a very mediocre Philips drive which helps xorriso
development by burning hardly readable media. My fine
Samsung can then revive the media by a new session.
Only the bad update session stays lost.)
Have a nice day :)