Re: [rdiff-backup-users] changed file format?

[Ben Escoto]

>>>>> Stephen Isard <address@hidden>
>>>>> wrote the following on Mon, 07 Jun 2004 13:21:34 +0100
> 
> I get:
> 
> Python 2.2.2 (#1, Feb 24 2003, 19:13:11)
> [GCC 3.2.2 20030222 (Red Hat Linux 3.2.2-4)] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
> >>> import time
> >>> time.daylight
> 1
> >>> time.localtime()
> (2004, 6, 7, 12, 36, 11, 0, 159, 1)
> >>> time.altzone
> -3600
> >>> time.timezone
> 0
> 
> ...
> >> error_log.2004-03-06T13:28:37+01:00.data.gz
> ..
> >> current_mirror.2004-03-06T13:28:37Z.data
> ...
> 
> Well, while we are on daylight saving time all the suffixes come out +01:00.
> The other arrangement should be reproducible when we go back on GMT.
> http://wwp.greenwichmeantime.com/time-zone/rules/eu.htm says that will be
> 31 Oct this year.
> 
> Although there is evidently some problem with the timestamps, I'm still not
> clear on what made my original test backup unreadable after I did a second
> one.  To recap, I did a backup with 0.12.3, producing wrong timestamps, then
> another with 0.12.6, producing correct timestamps (apart from the mysterious
> error log file) and then I couldn't list the earlier backup anymore.  Is the
> reason just that I did the two backups too close together, so that the 1 hour
> daylight saving error gave the first backup a later time than the second?  If
> I had left a couple of hours in between would I never have noticed the problem
> at all?  Here is a listing of the rdiff-backup-data directory for the test:
> 
> backup.log
> current_mirror.2004-03-06T13:28:37Z.data
> error_log.2004-03-06T13:26:34+01:00.data.gz
> error_log.2004-03-06T13:28:37+01:00.data.gz
> file_statistics.2004-03-06T13:26:34+01:00.data.gz
> file_statistics.2004-03-06T13:28:37Z.data.gz
> increments
> increments.2004-03-06T13:26:34Z.dir
> mirror_metadata.2004-03-06T13:26:34+01:00.snapshot.gz
> mirror_metadata.2004-03-06T13:28:37Z.snapshot.gz
> session_statistics.2004-03-06T13:26:34+01:00.data
> session_statistics.2004-03-06T13:28:37Z.data
> 
> The "Z" files were made by the second (0.12.6) backup and the "+01:00" ones by
> the first (0.12.3) backup.

That's a good theory about the first looking as if it were done after
the second, but shouldn't any confusion work in the opposite
direction?  13:26 at +01:00 should be 12:26 GMT.  Then if you make
another backup at 13:28 at GMT it should appear an hour and two
minutes later than the first one.

Hmm, actually on second thought I think you're right but have it
backwards.  The "Z" files were made by the first (0.12.3) backup
because it had a bug with daylight savings.  The "+01:00" files were
made by 0.12.6, and then appeared to be earlier than the previous
backup, causing various problems.  (Although rdiff-backup checks for
this; there should have been a "bad time error" or something.)

So anyway it seems that everything might be working now with recent
versions, except when python has the wrong time information, like on
Dave Kempe's cygwin setup.


-- 
Ben Escoto

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