It sounds as if what you are seeing is the natural delay while NetBackup 
scans the file system for files that are candidates for the incremental 
backup.    Until it does this and builds, then sorts, the list of files to 
backup - nothing gets written.

You can disable the sort phase, read this thread:

http://mailman.eng.auburn.edu/pipermail/veritas-bu/2005-January/026439.html

Note the warnings!  I think it is more relevant to full backups.  I don't 
think changing which file attribute is used will make a difference, so I'd 
suggest you don't.   In either case it has to access the file header (not 
the file data), so I can't see it making a performance difference.  You 
would have to read the Admin guide carefully to see if it might have 
unhelpful side-effects for you.

It will mean that if you need to restore say a whole directory, it may 
take longer as files will be on the tape in arbitrary order, I think.

William D L Brown




"Andrew Stueve" <andrew.stueve AT neovera DOT com> 
Sent by: veritas-bu-admin AT mailman.eng.auburn DOT edu
21-Sep-2005 17:12
 
To
veritas-bu AT mailman.eng.auburn DOT edu
cc

Subject
Re: [Veritas-bu] Archive bit vs timestamp






What do you mean by 'half way through the backup'? 

Do you mean the tape starts getting accessed halfway through?  Something
that might impact, is the number of files.  You are backing up 500gb,
but how many files are there?

-Andrew

Zermeno, Brandon (Contractor) wrote:

>I noticed that on my file servers the incremental starts backing up all
>files about half way through the backup. I run NBU 5.1mp3a on Windows.
>The file servers are Win 2000 advanced in a cluster. The node did not
>fail over during the backup. Is it due to the fact that I am backing up
>500 gig to a SDLT 220? The backup takes between 4 and 6 hours. Would
>setting my backups to be based on the timestamp be a better solution?
>
>Thanks
>Brandon
>
>_______________________________________________
>Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
>http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>
>
> 
>

-- 
Andrew Stueve
Neovera, Inc
571-437-5754
andrew.stueve AT neovera DOT com


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