Hi,

I've found through much experimentation (and some loss of Oracle archive
logs) that Networker doesn't appear to compare the current modification
time of each file to each file's previous modification time and backup
the file if the two times are different.

When the "save" command is executed on the client for an incremental
save, one of the arguments to "save" is a "-t <seconds>", where
<seconds> is the number of seconds since the Epoch when the last backup
occurred previous to the one that is just starting.

The "save" command will then backup all files who's modification time
occurs after the <seconds> value.  So Networker will backup all files
who's modification time occurs later than the time of the last backup
(for incremental saves).  While in the normal case this behaves exactly
like Anuj's post said, when you are dealing with BCV volumes on, say, a
SAN, it can bite you depending on how you setup the timing between BCV
splits and backups.  I've posted about this potential problem before to
this list.

On Tue, 2004-04-13 at 06:02, Anuj wrote:
> Hi,
>
> Any backup application compares the date stamp of last modification for each
> file with the one when it was backed up last time. The file contents may not
> have changed but the change in date stamp indicates that it has been
> modified and therefore needs to be backed up.
>
> Regards,
> Anuj
>
> ----- Original Message -----
> From: "Mariusz Bogumil" <marbo AT TPI DOT PL>
> To: <NETWORKER AT LISTMAIL.TEMPLE DOT EDU>
> Sent: Tuesday, April 13, 2004 3:43 PM
> Subject: [Networker] Incremantal backups in Legato Networker 6.1.4
>
>
> > I've go mysql database (on database each month is created. Updated are
> > only cerrent month databases, others are only historical without update)
> >
> > I've configured Legato Netowrker to do only incremental backups (im my
> > opinion only current month database), but sometimes (I have no idea why)
> > it makes very huge backup. Legato say it's incremantal backup not full
> > (in my opinion it is very similar to full, bacause I've got backed up
> > all files). UNIX ls shows that none of previous months files was changed
> > (but they are backed up).
> >
> > My question is::
> >
> > How Legato Networker that file was changed from last backup and should
> > be included to the current back up.
> >
> > Environment:: Sparc Solaris 8, Legato Networker 6.1.4
> >
> > Regards
> >
> > Mariusz Bogumil
> >
> > --
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>
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