Re: ADSM with Windows 2003 Server and SFU 3.5

True, TSM (like many other Win32 applications) does not support 
case-sensitive file names.

It isn't that we are willing to admit that such files exist; of course 
they exist. Nor is that we are "unwilling" to back up files supported by 
NTFS.

TSM, like any other application, relies on operating system API functions 
to operate on OS-specific elements (such as NTFS file systems and the 
files that reside thereon). NTFS supports the existence of case-sensitive 
file names, but there are limitations to the degree of support afforded by 
the OS API functions. Some of the issues involved:

- TSM needs to manage case-sensitive file names is differently than 
case-insensitive names (hopefully that is obvious). For non-Unix file 
names, NTFS is case-preserving, but case-insensitive. Thus 'README.TXT' 
and 'readme.txt' are the same file. TSM must operate on this file so that 
if the name changes from 'README.TXT' to 'readme.txt' between backup 
versions, TSM treats it as the same file. For case-sensitive file names, 
TSM must treat 'README.TXT' and 'readme.txt' as different files.

- Most Win32 applications are not case-sensitive with regard to file names 
(as noted below, there are some Windows API functions that support 
case-sensitive file names). Windows also provides a POSIX subsystem that 
allows POSIX applications to create case-sensitive names.

- Case-sensitive file names can coexist on the same volume with 
case-insensitive names. This means that at the NTFS volume level, an 
application can not make any blanket assumptions about the 
case-sensitivity of all files on the volume.

-  There is nothing in a file's attributes to indicate the case 
sensitivity. Therefore an application can not make any assumptions about 
the case-sensitivity of a given file.

- While some Windows file I/O functions support case-sensitive file names, 
others do not. For example, CreateFile(), which is used to open files, has 
support for case-sensitive file names; on the other hand, 
GetFileAttributes() (used to obtain a file's attributes) and 
GetFileSecurity() (used to obtain a file's security attributes) do not 
support case-sensitive file names. Thus if you have files 'readme.txt' and 
'README.TXT', we would not be able to obtain file attribute and security 
information for both files.

- Since, as stated above, TSM needs to manage case-sensitive file names 
differently than case-insensitive file names, TSM *must* be able to 
distinguish case-sensitive names from case-insensitive names. Since NTFS 
allows the existence of *both*, but provides no functionality to 
distinguish them, it is not possible for TSM to distinguish them, either.

In sum, while NTFS may allow case-sensitive file names to exist, the 
Windows operating system itself does not provide the functionality 
necessary to fully support these files. In fact, you will find that TSM is 
not the only application to have difficulty with case-sensitive files. For 
example, some basic OS functions like DIR or basic applications like 
NOTEPAD.EXE do not handle case-sensitive file names, either. Using some 
case-sensitive names I generated, the following is output from a sample 
session that demonstrates some odd behavior (note that "posix.exe" is a 
tool I created to generate case-sensitive file names):

==================================================
C:\POSIX>posix README.TXT ReadMe.txt readme.txt

C:\POSIX>dir
 Volume in drive C is Local Disk
 Volume Serial Number is B022-6D5D

 Directory of C:\POSIX

10/10/2003  10:47       <DIR>          .
10/10/2003  10:47       <DIR>          ..
10/10/2003  10:47                    0 README.TXT
10/10/2003  10:47                    0 ReadMe.txt
10/10/2003  10:47                    0 readme.txt
               3 File(s)              0 bytes
               2 Dir(s)   3,427,893,248 bytes free

C:\POSIX>echo Upper case name > README.TXT

C:\POSIX>echo Lower case name > readme.txt

C:\POSIX>echo Mixed case name > ReadMe.txt

C:\POSIX>dir
 Volume in drive C is Local Disk
 Volume Serial Number is B022-6D5D

 Directory of C:\POSIX

10/10/2003  10:47       <DIR>          .
10/10/2003  10:47       <DIR>          ..
10/10/2003  10:47                   18 README.TXT
10/10/2003  10:47                    0 ReadMe.txt
10/10/2003  10:47                    0 readme.txt
               3 File(s)             18 bytes
               2 Dir(s)   3,427,893,248 bytes free

C:\POSIX>type README.TXT
Mixed case name
Mixed case name
Mixed case name

C:\POSIX>type "README.TXT"
Mixed case name
Mixed case name
Mixed case name

C:\POSIX>type "ReadMe.txt"
Mixed case name
Mixed case name
Mixed case name

C:\POSIX>del "readme.txt"

C:\POSIX>dir
 Volume in drive C is Local Disk
 Volume Serial Number is B022-6D5D

 Directory of C:\POSIX

10/10/2003  10:48       <DIR>          .
10/10/2003  10:48       <DIR>          ..
               0 File(s)              0 bytes
               2 Dir(s)   3,427,893,248 bytes free

C:\POSIX>
==================================================

With all of that said, we are investigating ways to make TSM behave better 
than it does today, but I do not see a solution that fully supports 
case-sensitive names in the near- or medium-term, as we would need 
enhancements to the Windows APIs to facilitate such support.

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

The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.




Remco Post <r.post AT SARA DOT NL>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
10/10/2003 06:29
Please respond to "ADSM: Dist Stor Manager"
 
        To:     ADSM-L AT VM.MARIST DOT EDU
        cc: 
        Subject:        Re: ADSM with Windows 2003 Server and SFU 3.5


On Fri, 10 Oct 2003 15:06:40 +0200
Gregor Küpper <kuepper AT INFORMATIK.UNI-BONN DOT DE> wrote:

> Hi,
> 
> we have a installation with a Windows 2003 Cluster and Microsoft
> Services for UNIX SFU 3.5
> In SFU we enable case sensitive filename processing. ( AAA.txt is not
> the same as aaa.txt )
> We are able to backup these files, but cannot restore them.
> The error message is: file already exist
> Who can help us?
> 
> Regards,
> 
> Gregor K|pper

IBM can. As soon as Tivoli is ready to admit that it is a feature of the
NTFS filesystem to be not only case preserving, but also case-sensitive, 
and
they are ready to admit that is is their job to be able to backup and
restore all files that can legally excist on a NTFS filesystem.

Basically IBM claims WAD, NTFS is not supposed to be used in a case
sensitive way, so we don't support that....

-- 
Met vriendelijke groeten,

Remco Post

SARA - Reken- en Netwerkdiensten                      http://www.sara.nl
High Performance Computing  Tel. +31 20 592 8008    Fax. +31 20 668 3167

"I really didn't foresee the Internet. But then, neither did the computer
industry. Not that that tells us very much of course - the computer 
industry
didn't even foresee that the century was going to end." -- Douglas Adams