Re: Backing up Linux to Windows 10

From	"Carlos E.R." <robin_listas@es.invalid>
Newsgroups	alt.os.linux
Subject	Re: Backing up Linux to Windows 10
Date	2026-03-23 11:03 +0100
Message-ID	<3of79mx36k.ln2@Telcontar.valinor> (permalink)
References	(4 earlier) <10pq2uc$3occt$1@dont-email.me> <10pq54h$3ov0q$1@dont-email.me> <10pq6ql$3pen6$1@dont-email.me> <9hl69mx2p3.ln2@Telcontar.valinor> <10pqd2u$3r45e$1@dont-email.me>

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On 2026-03-23 04:46, Paul wrote:
> On Sun, 3/22/2026 10:35 PM, Carlos E.R. wrote:
>> On 2026-03-23 02:59, Paul wrote:
>>> On Sun, 3/22/2026 9:30 PM, Lawrence D’Oliveiro wrote:
>>>> On Sun, 22 Mar 2026 20:53:32 -0400, Paul wrote:
>>>>
>>>>> He described a timestamp problem, so no information loss was
>>>>> involved. Inefficient extra copying went on, because the process
>>>>> thought the date on the file had changed (and it had changed, just
>>>>> not for the expected reason).
>>>>
>>>> Loss of timestamp info on the previously-backed-up files *does* count
>>>> as “information loss”. Something corrupted that info on disk.
>>>>
>>>
>>> It's not loss, it is interpretation. It's a design issue.
>>>
>>> There is little reason for all files to be synced because
>>> the software has detected a one hour difference (for example).
>>> That could happen on FAT32 with the DST change.
>>>
>>> When two systems systems do not share up-to-date TZINFO, there can be
>>> artificial changes that way. I have occasionally seen OSes I've booted
>>> be off by an hour, and even when it is not a TZ change date.
>>>
>>> You can see these cases in discussion threads Google throws up,
>>> and in some of them, a "USB stick with FAT32" not mentioned
>>> in the original question, is the culprit. FAT32 uses localtime,
>>> EXFAT uses UTC apparently, but with different granularity
>>> than NTFS.
>>>
>>> You have to put on your timelord hat and start searching
>>> around for the source of the mis-interpretation.
>>
>> Arguably, that software is not saving the metadata of the Linux files correctly. The time stamping on the Windows machine should be irrelevant. For each Linux file, the software should store separately the file itself, and the original metadata somewhere else, because Windows can not store Linux filesystem metadata. And if that metadata is stored separately, there can not be interpretation errors about the timestamp later, even if the TZ or DST change later.
>>
>> My guess is that the software is storing the Linux files as Windows files, so attributes and metadata get lost. Which may be irrelevant, if all they are are movies. But if it is a system backup, then important metadata will be lost. Also symlinks, hardlinks, sparse files, etc.
>>
> 
> https://www.2brightsparks.com/syncback/help/profeatures.htm?srsltid=AfmBOorAVDr3ASLAZGzZUuju4aBi34LQzlddH28yrmtuyxjmpyhvo4z5
> 
>      "SyncBackPro uses a database to store details of the files it is copying,"
> 
> I think that means, when doing something in the incremental sense, the
> satellite software that sweeps a foreign computer, it is going to
> forward information in some format local to it, and that has
> to be compared to what is in the database. The database is loaded
> with metadata also obtained from the format local to the remote machine.
> 
> If the handing on the remote machine does not have good temporal integrity,
> the problem may start on the foreign end.
> 
> *******
> 
> One thing we learn about calibrating backup software, is the need
> to use multiple methods and compare what is happening with all of them.
> In an attempt to spot inconsistency.
> 
> You might need, say, a directory listing from before the time change.
> 
> Wed, 09/17/2025  03:59 PM           255,125 zenity-dialog-02.png
> Wed, 09/17/2025  04:05 PM            95,679 zenity-dialog.gif
> Wed, 09/17/2025  03:34 PM           225,469 zenity-dialog.png
> 
> Then today, we check them again. Are they the same ?
> 
> Well, one problem would be, that the OS you're observing that with,
> could have the same problem as the backup is seeing. Or, you would
> hope so, if trying to detect an errant time change.
> 
> One of the problems I've been working on for some time, is the
> incompleteness of file listing programs. Rather than anything
> to do with datestamps. I don't keep file lists here as an
> integrity check, rather most of the files I keep they have
> lists of filenames (basically, to see if there will ever be
> a method that lists everything). I'm not even set up, not
> on any platform, for time-related issues. And that also means,
> I'm more likely to have not recommended to people that they
> keep ls -algtR listings as a means of detecting some sort of
> modification. I would be more likely to be using hashdeep for that
> (looking for content changes).
> 
> For the SyncBack software, you'd want to look inside the database
> it keeps, to see the date information kept there. Presumably if
> you were restoring, various versions of files should be listed,
> along with their (foreign collected) datestamp information.
> 
> It's also possible that Jeff is in a place where there are
> two timezones, and occasionally the wrong time zone is set
> on an OS in the location department. Or, some software is
> not aware there are two timezones. That would be for local time
> determination.

But that is precisely the issue I am saying. The filesystems in Linux do 
not have timezones, nor summer/winter time differences. They use Unix 
time, or UTC.

To convert this properly and saved in Windows, you have to store the 
Linux side information separately from the Windows filesystem metadata. 
In a database, for example. And when doing backups or restore, the 
windows side metadata has to be ignored, and instead, the metadata, the 
time stamps, have to be backed up or restored from the database.



-- 
Cheers, Carlos.
ES🇪🇸, EU🇪🇺;

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Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-22 15:20 +0000
  Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-03-22 14:06 -0400
  Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-22 20:58 +0000
    Re: Backing up Linux to Windows 10 Richard Kettlewell <invalid@invalid.invalid> - 2026-03-22 21:08 +0000
      Re: Backing up Linux to Windows 10 Dan Purgert <dan@djph.net> - 2026-03-31 00:07 +0000
    Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-03-22 17:51 -0400
    Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-22 21:59 +0000
      Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-22 23:57 +0000
        Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-03-22 20:53 -0400
          Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-23 01:30 +0000
            Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-03-22 21:59 -0400
              Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-23 02:07 +0000
              Re: Backing up Linux to Windows 10 "Carlos E.R." <robin_listas@es.invalid> - 2026-03-23 03:35 +0100
                Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-03-22 23:46 -0400
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-23 04:43 +0000
                Re: Backing up Linux to Windows 10 "Carlos E.R." <robin_listas@es.invalid> - 2026-03-23 11:03 +0100
          Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-23 08:48 +0000
            Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-23 09:56 +0000
              Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-03-23 07:37 -0400
              Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-24 01:24 +0000
                Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-03-24 00:31 -0400
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-24 05:37 +0000
                Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-24 08:38 +0000
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-24 09:20 +0000
                Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-24 09:46 +0000
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-04 05:44 +0000
                Re: Backing up Linux to Windows 10 rbowman <bowman@montana.com> - 2026-03-24 17:46 +0000
            Re: Backing up Linux to Windows 10 dillinger <dillinger@invalid.not> - 2026-03-23 11:06 +0100
        Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-23 08:42 +0000
          Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-23 19:12 +0000
            Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-23 22:00 +0000
              Re: Backing up Linux to Windows 10 vallor <vallor@vallor.earth> - 2026-03-23 23:17 +0000
                Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-24 08:46 +0000
              Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-03-24 01:01 +0000
                Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-03-24 08:44 +0000
                Re: Backing up Linux to Windows 10 vallor <vallor@vallor.earth> - 2026-03-24 15:57 +0000
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-04 05:42 +0000
  Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-14 12:30 +0000
    Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-14 09:51 -0400
      Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-14 15:04 +0000
      Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-14 21:58 +0000
        Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-15 07:44 +0000
          Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-15 04:53 -0400
            Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-15 12:31 +0000
              Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-15 09:42 -0400
                Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-15 14:25 +0000
                Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-16 05:50 -0400
                Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-16 09:53 +0000
                Re: Backing up Linux to Windows 10 "Carlos E.R." <robin_listas@es.invalid> - 2026-04-16 12:35 +0200
                Re: Backing up Linux to Windows 10 Richard Kettlewell <invalid@invalid.invalid> - 2026-04-16 20:37 +0100
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-20 00:23 +0000
                Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-20 04:31 -0400
                Re: Backing up Linux to Windows 10 "Carlos E.R." <robin_listas@es.invalid> - 2026-04-20 12:06 +0200
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-21 01:08 +0000
                Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-21 08:04 -0400
                Re: Backing up Linux to Windows 10 "Carlos E.R." <robin_listas@es.invalid> - 2026-04-21 22:52 +0200
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-21 21:19 +0000
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-21 22:13 +0000
              Re: Backing up Linux to Windows 10 Daniel70 <daniel47@nomail.afraid.org> - 2026-04-16 00:04 +1000
                Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-15 14:23 +0000
                Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-16 06:05 -0400
                Re: Backing up Linux to Windows 10 Daniel70 <daniel47@nomail.afraid.org> - 2026-04-16 20:16 +1000
                Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-16 08:53 -0400
    Re: Backing up Linux to Windows 10 "Carlos E.R." <robin_listas@es.invalid> - 2026-04-14 15:51 +0200
      Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-14 11:01 -0400
        Re: Backing up Linux to Windows 10 "Carlos E.R." <robin_listas@es.invalid> - 2026-04-14 20:39 +0200
        Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-14 21:56 +0000
          Re: Backing up Linux to Windows 10 "Carlos E.R." <robin_listas@es.invalid> - 2026-04-15 10:57 +0200
            Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-15 07:06 -0400
    Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-14 21:55 +0000
      Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-15 07:40 +0000
        Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-15 04:55 -0400
        Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-15 22:18 +0000
          Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-16 07:38 +0000
            Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-16 07:55 +0000
              Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-16 08:40 +0000
                Re: Backing up Linux to Windows 10 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-04-16 09:03 +0000
                Re: Backing up Linux to Windows 10 "Jeff Gaines" <jgnewsid@outlook.com> - 2026-04-16 09:06 +0000
                Re: Backing up Linux to Windows 10 Paul <nospam@needed.invalid> - 2026-04-16 06:40 -0400

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