Steve,
Try as I might, I cannot locate this white paper on the IBM web site.
Netiher looking at the white papers section from the web page nor a general
keyword search yields anything for me.
Anyway...
Re: File ownership permissions: Normally the restore of a subfile backup
should yield a file with the original NT security attributes. The caveat
you cite has to do with the case where the file owner has removed the
necessary permissions required by the account doing the restore; in such a
case, the file cannot be moved back to its original location after
reconstruction. The test flag will cause the account doing the restore to
take ownership of the file, after which the file can be moved back to its
original location. In general, I would not expect mobile users (the target
audience for subfile backup) to run into such issues, but for file
serveers, the odds are more likely that you could run into such situations.
The code hasn't changed in this regard since the time the paper was
writtten.
Re: not recommended for databases: I didn't write the paper, so I don't
know why this recommendation was made. Possible reasons include:
- Databases are sensitive data repositories, and it is always a good idea
to follow the database vendor's recommendation for backup (or use a DP
product if available).
- Because of the manner in which data can change in a database, in general,
they are not good candidates for subfile backup, i.e., there is little
benefit in using subfile backup.
Regards,
Andy
Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Development
Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
Internet e-mail: storman AT us.ibm DOT com
IBM Tivoli Storage Manager support web page:
http://www-306.ibm.com/software/sysmgmt/products/support/IBMTivoliStorageManager.html
The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.
"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 2005-12-28
17:38:57:
> Thanks for the reply Andy
>
> The whitepaper is titled "Tivoli Storage Manager Adaptive Sub-file
> Differencing and Encryption for Mobile and Remote Clients" which I
> downloaded last week from the white papers portion of the Tivoli Support
> Section of the IBM website.
>
> On page 9 it states
>
> ===============================================
> Backing Up Databases
>
> Adaptive sub-file differencing is not recommended
> for backing up databases.
>
> ===============================================
>
> Followed by
>
> ===============================================
> File Ownership Permissions
>
> Microsoft Windows does not provide a way to copy
> all non-file data from one file to another, for
> example, Windows NT¨ Security data, AFP data, and
> non-named streamed data. This limits the recombination
> of the reference and delta files on Tivoli
> Storage Manager. To perform the recombination,
> and keep the temporary reference and delta files
> separated from valid data, the reconstruction takes
> place in the /~tsmptemp directory. The person
> restoring the files must be the owner of the files or
> have read or write permission, to successfully copy
> the reconstructed file from the /~tsmtemp directory
> to the desired restore location. When a
> Windows administrator performs the restore, the
> administrator owns the resulting file, not the original
> owner. The administrator must specify
> 'TESTFLAG TAKEOWNERSHIP' in the dsm.opt file to
> assign ownership.
> ===============================================
>
> Then immediately following, on page 10 it states
>
> ===============================================
> Backing Up File Servers
>
> File servers should not be backed up using adaptive
> sub-file differencing. This is because the
> person performing the restore may not have the
> same permissions as the owner of the file and file
> ownership problems described in the preceding
> paragraph will be encountered.
>
> ===============================================
>
> The whitepaper is dated 2000 and I suppose that it is possible that the
> Windows API has changed since then, or the capabilities of the client may
> have changed since then. The question is whether the recommendations are
> still accurate, as always with the YMMV disclaimer.
>
> Regards
>
>
> Steve.
>
>
> > -----Original Message-----
> > From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]
> > On Behalf Of Andrew Raibeck
> > Sent: Thursday, 29 December 2005 2:11 AM
> > To: ADSM-L AT VM.MARIST DOT EDU
> > Subject: Re: [ADSM-L] Adaptive Subfile Backup and File Servers
> >
> >
> > Hi Steve,
> >
> > To what adaptive subfile white paper do you refer? Subfile
> > backup does indeed back up the security attributes for files.
> > Of course, questions such as these can always be resolved by
> > testing them out for yourself.
> >
> > As to how effective subfile backup is for the types of files
> > you mention, I do not know for sure. It depends on how the
> > underlying blocks of data are changed on the disk. For
> > example, if data is inserted at the front of a file, that
> > could cause all the blocks to appear as changed, so the next
> > subfile backup backs up the entire file. On the other hand,
> > if you add data to the end of an existing file, then the next
> > subfile backup is more likely to back up only those new
> > blocks that were added. If changes to MS Access files tend to
> > change blocks throughout the file, then subfile backup might
> > not afford much benefit. For .pst files, I think other users
> > have reported success with subfile backup. You might try
> > searching the ADSM-L archives for earlier discussions on that subject.
> >
> > Since Exchange is a TSM API application, and the API does not
> > use subfile backup, I do not understand the reference you mention.
> >
> > Regards,
> >
> > Andy
> >
> > Andy Raibeck
> > IBM Software Group
> > Tivoli Storage Manager Client Development
> > Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
> > Internet e-mail: storman AT us.ibm DOT com
> >
> > IBM Tivoli Storage Manager support web page:
> > http://www-306.ibm.com/software/sysmgmt/products/support/IBMTi
> > voliStorageManager.html
> >
> >
> > The only dumb question is the one that goes unasked.
> > The command line is your friend.
> > "Good enough" is the enemy of excellence.
> >
> > "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 2005-12-27
> > 18:50:33:
> >
> > > Hi All
> > >
> > > Compliments of the season to all our regulars!
> > >
> > > I have a client with a largish file server on a Windows
> > 2000 Cluster.
> > > Analysis of a recent schedlog shows that on this particular
> > day, 87%
> > > of the data backed up was .pst files, something that I'm sure is
> > > rather common where Outlook is the mail client.
> > >
> > > Now the obvious suggestion is to use Adaptive Subfile
> > Backup for these
> > > and only back up the bits that have changed, but my boss
> > pointed out
> > > that the Adaptive subfile whitepaper suggests that its use is not
> > > indicated for file servers. The reason given for this is that ASB
> > > cannot restore windows acls. Now on this file server all
> > of the .pst
> > > files that I looked at inherited their permissions from
> > their parents
> > > so, I'm thinking that for the average Joe user, this
> > limitatioon would
> > > not be an issue. All restores on this system would normally
> > be done by
> > > the administrator anyway.
> > >
> > > So, is the recommendation in the white paper correct? Do
> > any of you
> > > use Adaptive Subfile with .pst files on file servers and if so have
> > > there been any issues?
> > >
> > > Also two supplementary questions. The next largest category of
> > > backups on this server is access databases. Again the whitepaper
> > > recommends against using adaptive subfile on these. Might
> > I ask the
> > > same questions for .mdb files?
> > >
> > > Finally, I was looking at a Dave Canaan slide show from a
> > 2003 Share
> > > conference where he explained how ASB works. There is one
> > line in the
> > > powerpoint that states that Adaptive Subfile is also available for
> > > Exchange. I've searched through the TDP for Exchange documentation
> > > and can find no reference. Was this just a typo, a deleted
> > feature or
> > > what?
> > >
> > > Regards and felicitations
> > >
> > > Steve.
> > >
> > > Steven Harris
> > >
> > > AIX and TSM Administrator,
> > > Brisbane Australia
> > > steve AT stevenharris DOT info
> >
> >
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