Re (2): Time stamps on sessions on a DVD backup.

2023-08-12 Thread peter 
From: "Thomas Schmitt" 
Date: Sun, 13 Aug 2023 00:08:23 +0200
> You would have to load each session and inquire it:

OK, thanks.

> Having an id for the backup script makes it possible to ensure that the
> script is not applied to the medium of a different backup script.

Good, thanks, ... P.



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Re: Time stamps on sessions on a DVD backup.

2023-08-12 Thread Thomas Schmitt 
Hi,

pe...@easthope.ca wrote:
> Session time stamps would help when recovering from a
> storage failure.  Eg.
>
> DateTOC layout   : Idx ,  sbsector ,   Size , Volume Id
> 2023-07-23  ISO session  :   1 , 0 ,678303s , ISOIMAGE
> 2023-07-29  ISO session  :   2 ,716368 , 13376s , ISOIMAGE
> 2023-08-06  ISO session  :   3 ,737600 ,816699s , ISOIMAGE
>
> Can the current xorriso include session timestamps?  In the manual I
> see file timestamps mentioned.  Not session timestamps.

Currently only the creation time of the loaded session is in reach:

  $ xorriso -indev /dev/sr0 -pvd_info
  ...
  Creation Time: 2023081220110500
  ...

You would have to load each session and inquire it:
  $ xorriso -load session 1 -indev /dev/sr0 -pvd_info
  ...
  Creation Time: 2023072920104300
  ...

I encode the time in the volume id together with an id of the backup
script (here "HOME_Z"):

  xorriso \
... \
-dev /sr0 \
... \
-volid HOME_Z_"$(date '+%Y_%m_%d_%H%M%S')" \
...

The backup medium then bears a -toc like:

  TOC layout   : Idx ,  sbsector ,   Size , Volume Id
  ISO session  :   1 ,32 ,   1213035s , HOME_Z_2023_07_29_220901
  ISO session  :   2 ,   1213088 , 19527s , HOME_Z_2023_07_30_223447
  ISO session  :   3 ,   1232640 , 17993s , HOME_Z_2023_07_31_214713
  ...
  ISO session  :  12 ,   1403136 , 19367s , HOME_Z_2023_08_10_223506
  ISO session  :  13 ,   1422528 , 15773s , HOME_Z_2023_08_11_222313
  ISO session  :  14 ,   1438304 , 16758s , HOME_Z_2023_08_12_221015

Having an id for the backup script makes it possible to ensure that the
script is not applied to the medium of a different backup script.
Before loading the youngest session by -dev, i set the constraint

  -assert_volid 'HOME_Z_2*' FATAL \

which will let the next -dev command fail if the volume id does not match
the pattern 'HOME_Z_2*' or is (pseudo-)blank.


Have a nice day :)

Thomas

Time stamps on sessions on a DVD backup.

2023-08-12 Thread peter 
Hello again,

Here a session of a backup archive is written to a DVD.

xorriso -for_backup -dev /dev/sr0 \
  -update_r . / \
  -commit \
  -toc -check_md5 failure -- \
  -eject all
 
This command gives the contents of a DVD.
  xorriso -dev /dev/sr0 -toc

TOC layout   : Idx ,  sbsector ,   Size , Volume Id
ISO session  :   1 , 0 ,678303s , ISOIMAGE
ISO session  :   2 ,716368 , 13376s , ISOIMAGE
ISO session  :   3 ,737600 ,816699s , ISOIMAGE
  ...

Session time stamps would help when recovering from a 
storage failure.  Eg.

DateTOC layout   : Idx ,  sbsector ,   Size , Volume Id
2023-07-23  ISO session  :   1 , 0 ,678303s , ISOIMAGE
2023-07-29  ISO session  :   2 ,716368 , 13376s , ISOIMAGE
2023-08-06  ISO session  :   3 ,737600 ,816699s , ISOIMAGE

Can the current xorriso include session timestamps?  In the manual I 
see file timestamps mentioned.  Not session timestamps.

Thx,   ... P.

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