Veritas-bu

[Veritas-bu] What if differential doesn't have a full backup?

2001-10-18 11:43:47
Subject: [Veritas-bu] What if differential doesn't have a full backup?
From: larry.kingery AT veritas DOT com (Larry Kingery)
Date: Thu, 18 Oct 2001 11:43:47 -0400 (EDT)
On unix, the differential backup is based on the beginning of the last
backup in the same class.  So if there's no full, then everything will
"have changed" and you'll effectively get a full backup.  That is to
say that everything will be backed up, it's not really a full backup
(I make the clarification mostly because not having a full may affect
subsequent cumulative backups).

On windows, I don't know how or when the archive bit is used, but I
think it was just discussed thoroughly. 

Sixbury, Dan writes:
> I just ran across two classes that run on the same server.  One class has
> one schedule that does a full backup of multiple file systems that contain
> oracle data in them.  This is used for a cold oracle backup.
> 
> Another class is for the same server but is doing all of the file systems
> that are not included in the first class.  However, this backup is a
> differential incremental.  
> 
> 1.  Doesn't a full backup have to be associated with the class, or will
> NetBackup realize that another class is performing a full backup?
> 
> 2.  Since the differential incremental has different file systems from the
> full backup, I would assume that the first time the differential incremental
> is run that it would perform a full backup of all of its selected file
> systems and then the rest of the week pick up only the changes.  Is that the
> correct assumption?
> 
> My only concern would be that something is not getting backed up with these
> two classes even though all file systems are selected between the two
> classes and schedules.  I guess one of the questions here would be if you
> run a differential incremental backup and haven't run a full backup, does
> that mean the first differential is equivalent to a full backup or does it
> mean that you have put yourself into an unrecoverable situation?   And how
> does having different files selected for your full backup and for your
> differential incremental backup affect your backup/recovery?
> 
> My only disclaimer is that I didn't set these two classes up.  ;-)
> 
> thanks,
> Dan
> _______________________________________________
> Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu

-- 
Larry Kingery 
       Don't anthropomorphize computers -- they don't like it.