The earlier description on subfile backup is not correct.

The cache does NOT hold a copy of the original file for files > 3M.
It keeps a file that stores a MAP of the blocks of the original file.
The TSM Server stores the original file, and the subfile differences.
At restore time, the original file is restored and the subfile
differences.
The map is used to update the original base file to bring it to the
correct state.

As for what is stored in the cache...
For 1K < file size < 3M, the cache holds a copy of the file data
For 3M < file size, the cache holds the block signature map
As stated earlier, files > 2G are not eligible for subfile backup.

Thanks,

Del
----------------------------------------------------

"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 02/14/2008
11:15:58 AM:

> At 11:04 PM 2/13/2008, Wanda Prather wrote:
> >Subfile backup was designed to work on laptops, not servers.
>
> Yes, that is what we are trying to do.  Sam, on the other hand....
>
> >The "base" or initial backup copy of a file is stored in a cache
directory
> >on the client, which is also limited in size to 2 GB.
>
> I didn't realize the cache directory was limited in size and that it
held
> complete copies of files.  Checking this, it seems you may be correct
about
> full copies of files being made in the cache directory.  The size of the
> cache directory is only 1GB according to the Users Guide, and that is
what
> the EditPreferences GUI restricts you to as well....  I don't understand
> how subfile backup can work for files up to 2GB in size, if the
> subfilecachesize is restricted to 1024 MB.
>
> >In short, you can only manage a total of about 2 GB of files for
subfile
> >backup, and only files less than 2 GB in size are eligible.
>
> Bummer.  Thanks Wanda.
>
> ..Paul
>
>
> --
> Paul Zarnowski                            Ph: 607-255-4757
> Manager, Storage Services                 Fx: 607-255-8521
> 719 Rhodes Hall, Ithaca, NY 14853-3801    Em: psz1 AT cornell DOT edu