Veritas-bu

[Veritas-bu] Fragment size settings

2001-10-17 14:48:46
Subject: [Veritas-bu] Fragment size settings
From: rob AT worman DOT org (Rob Worman)
Date: Wed, 17 Oct 2001 13:48:46 -0500
Are you saying that a Solaris version that doesn't support largefiles 
(ignoring the fact that that vintage of Solaris is no longer supported 
by NBU > 3.2...) would not be able to extract files from a tape that 
contains a 10 GB tar file?  I can't disprove this fact, but I can doubt 
it.  ;-)

rob

Zufall, Ken wrote:

>Fragmentation shouldn't be a problem.  Not sure about NBU, but other
>applications I've worked with won't cut a file in the middle of a fragment,
>it will continue to end of current file.  So, if you've already backed up
>1.5GB and the next file is .7MB, your fragment size will be 2.2GB.  Not
>using fragmentation will cause problems however, because some systems
>(Solaris 2.5 for sure, think they finally fixed in 2.7?) won't allow file
>sizes over 2GB in size.  So a 10GB tar file would be unmanageable in this
>instance.
>
>Ken Zufall
>Work: 330.202.4113
>Cell: 330.465.8113
>Pager: 888.896.3272
>E-page: 4403037243.8963272 AT pagenet DOT net
><mailto:4403037243.8963272 AT pagenet DOT net> 
>
>               -----Original Message-----
>               From:   Rob Worman [mailto:rworman AT yahoo DOT com]
>               Sent:   Wednesday, October 17, 2001 11:56 AM
>               To:     EBU (E-mail)
>               Subject:        Re: [Veritas-bu] Fragment size settings
>
>               and I know of one price you pay for the use of fragment
>size: 
>               complication of a "non-NBU" tape restore, i.e. reading from
>a NetBackup 
>               tape using only tar.
>
>               Without fragmentation, a single 10GB backup image = a single
>10GB tar 
>               file. But with a fragment size of 2000, that 10GB backup
>image is now 5 
>               separate tar files.
>
>               Unlike the use of multiplexing, fragmenting is not
>necessarily a 
>               "showstopper" when considering this aspect of NetBackup's DR
>
>               capabilities, but if you really want to be prepared for
>tar-only 
>               NetBackup restores, you MUST understand the effect
>fragmentation has on 
>               your media contents. (and you'd be smart to write a script
>to automate 
>               all the tar commands...)
>
>               HTH
>               rob
>
>
>               Kyle Adamski wrote:
>
>               > The theory behind the fragment size setting on the storage
>unit is to 
>               > break the larger tar images into smaller fragments. This
>allows 
>               > restores to speed up because in between the fragments is a
>tape mark 
>               > (identifying what is on the fragment) that will allow NBU
>to scan the 
>               > tape faster for what it is looking for vs reading the
>entire image. We 
>               > use them and have them set at 2G....I have never tested
>the speed of 
>               > restores with and without them....I have just accepted
>them in 
>               > principle and assumed that they worked as advertised. If
>you have them 
>               > set at 0(unlimited) there will be no fragmentation.
>               >
>               > Hope that helps.
>               >
>               > Kyle A. Adamski
>               >
>               > kylea AT firstlogic DOT com
>               >
>               > 608.788.8154 x3093
>               >
>               > -----Original Message-----
>               > From: Brochart, Fabrice [mailto:BrochF AT europe.stortek DOT 
> com]
>               > Sent: Wednesday, October 17, 2001 9:23 AM
>               > To: 'Sixbury, Dan'; EBU (E-mail)
>               > Subject: RE: [Veritas-bu] Fragment size settings
>               >
>               > Hi ,
>               >
>               > I read somewhere that restore is more faster with fragment
>size 
>               > (depend on size (depend on backup :) ))
>               >
>               > And some customers tells me the same things but I've never
>verified.
>               >
>               > HTH
>               >
>               > F@brice
>               >
>               > -----Message d'origine-----
>               > De : Sixbury, Dan [mailto:sixbury AT celeritas DOT com ]
>               > Envoyé : mercredi 17 octobre 2001 16:00
>               > À : EBU (E-mail)
>               > Objet : [Veritas-bu] Fragment size settings
>               >
>               > Has anyone seen any benefits for using fragment size on
>the storage units,
>               > or have reasons to not use fragment sizes? I think the
>default is
>               > unlimited, but I noticed that we had some storage units
>that were set to
>               > 2000 while others had the default of unlimited.
>               >
>               > Thanks,
>               > Dan
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>
>
>
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