Thanks for the clarification Ueli, i got what you mean and also understand the 
trade off of having faster backup speed. :) 



Ueli Schweizer wrote:
> Flashbackup backups data by reading block after block (physical order). If a
> file is not stored in consecutive blocks on disk it will not be stored in
> consecutive blocks on tape. If you restore such a file the data has to be
> collected from different positions of a tape or, even worst, from different
> positions on multiple tapes. That of course leads to slower file restores,
> although NetBackup does a great optimization job on that.
> 
> This disadvantage is as bigger as more fragmented your data on disk is.
> 
> On the other hand, if you need to restore the whole disk it will be much
> faster, because you read consecutive disk blocks from tape and there is
> nearly no disk positioning necessary.
> 
> Ueli Schweizer
> CTO
> 
> AGITE Software AG · Boesch 43 · CH-6331 Huenenberg · Switzerland
> Direct: +41 79 204 9190 · Phone: +41 41 781 5678 · Fax: +41 41 781 5677
> Ueli.Schweizer < at > AGITE-Software.com · http://www.AGITE-Software.com 
> 
> backupVISUAL?...
> ...we make life on backup easy
> 
> -----Original Message-----
> From: veritas-bu-bounces < at > mailman.eng.auburn.edu
> [mailto:veritas-bu-bounces < at > mailman.eng.auburn.edu] On Behalf Of dy018
> Sent: Wednesday, July 02, 2008 11:33 AM
> To: VERITAS-BU < at > mailman.eng.auburn.edu
> Subject: [Veritas-bu] NBU Flashbackup vs Normal Backup
> 
> 
> Thanks everyone for your input.
> 
> BTW Ueli, can i ask you abt slow restore. You mention for single file
> restore require various tape positioning, meaning to restore 1 file, it need
> to position the tape afew time before restoring the entire file? whereas a
> normal filesystem backup when retore a single file only require 1 time
> postioning? So the multiple times taken for the positioning wil affect the
> overall restore timing?
> 
> 
> 
> Ueli Schweizer wrote:
> 
> > Data fragmented on disk will also be backed up fragmented using
> > 
> Flashbackup.
> 
> > The restore of single files will be slower in this case, because the 
> > data cannot be restored without various tape positioning.
> > 
> > Ueli Schweizer
> > CTO
> > 
> > AGITE Software AG 7 Boesch 43 7 CH-6331 Huenenberg 7 Switzerland
> > Direct: +41 79 204 9190 7 Phone: +41 41 781 5678 7 Fax: +41 41 781 
> > 5677 Ueli.Schweizer < at > AGITE-Software.com 7 
> > http://www.AGITE-Software.com
> > 
> > backupVISUAL...
> > ...we make life on backup easy
> > 
> > 
> > -----Original Message-----
> > From: veritas-bu-bounces < at > mailman.eng.auburn.edu 
> > [mailto:veritas-bu-bounces < at > mailman.eng.auburn.edu] On Behalf Of 
> > dy018
> > Sent: Wednesday, July 02, 2008 5:02 AM
> > To: VERITAS-BU < at > mailman.eng.auburn.edu
> > Subject: [Veritas-bu] NBU Flashbackup vs Normal Backup
> > 
> > 
> > Hi,
> > 
> > Recently i was told by symantec that using Flashbackup to backup the 
> > raw device will greatly increased the backup and restore time.
> > 
> > After reading through the admin guide abt the advanced client, i also 
> > understand that flashbackup also able to do file level restore instead 
> > on restoring the entire volume which i initially tot is going to be 
> > the trade off.
> > 
> > This spark a question, so a flashbackup is almost the same as a normal 
> > file level based backup which also able to retore individual files, 
> > wat are the cons of using flashbackup beside higher cost to buy the 
> > advanced client licenses? Anyone here knows the pros and cons?
> > 
> > Regards
> > 
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