|After a change into or out of Daylight Time, FileBack PC re-copies all of my backup files|
FileBack PC uses the time stamp of files to determine if
they have changed. It compares the modification date and time of the files
in the source folder with the modification date and time of the files in the
destination folder, and if there is a difference, it considers this a change
in the file and performs another backup. Normally this works perfectly,
except when the time stamps of the files change due to a change in daylight
The underlying problem is actually caused by a
difference in the way that time stamps are handled with the different file
systems used by Windows (NTFS and FAT32). The time stamp stored by NTFS uses
an absolute time (GMT) that is converted to your local time whenever you
access a file on an NTFS disk. FAT32, on the other hand, stores the time
stamp in local time. So what happens when your computer changes in our out
of daylight time (or you change the time zone setting) is that the time stamps
on all files on NTFS drives appear to change, whereas time the time stamps
on FAT32 drives do not.
Why does FileBack PC appear to behave erratically?
If a backup job in FileBack PC accesses files using two different file
systems, NTFS on the source, and FAT32 on the destination, for example, this
causes the date stamps to be out of sync after a time change. So to bring them back into sync
FileBack PC has to recopy or resynchronize all files.
The problem has been analyzed here at Maximum Output Software and we have
determined that there isn't an easy way to handle this
situation. There are too many possible scenarios to properly address them
all (a few examples: How do we determine what time zone the computers
containing the source and destination folders are in? -- there is no way to
determine the time zone of a remote or networked computer. Are they
currently observing daylight time? -- same issue. Which file system
contains the "correct" date/time for a file?). So we recommend that (1) the same file system be used on all
disks that FileBack PC is set to use, or (2) allow this backup to take place
twice per year whenever going into or out of daylight time.
We are aware of your concern but at this time no other
solution is available. The underlying problem is due to a fundamental difference between NTFS and FAT32, and this is not a bug or design flaw with FileBack PC.
|Keywords: daylight, recopy, recopies; Applies to: FileBack PC (All versions)||Was this article helpful? Yes No