TSM does not use the NT Backup APIs; rather, it uses the Win32 File I/O
functions for accessing files.
Regards,
Andy
Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Development
Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
Internet e-mail: [EMAIL PROTECTED]
The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.
Allan Kelly <[EMAIL PROTECTED]>
Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]>
04/02/2002 13:03
Please respond to "ADSM: Dist Stor Manager"
To: [EMAIL PROTECTED]
cc:
Subject: Re: Windows NTFS last accessed date set by TSM client
I was away for most of the past week and am just getting back to this
question now. I passed the thread on to our NTFS guy because we are still
having problems with the last accessed date being set during TSM backup
scheduled runs on our file servers (these servers are virus protected with
CA's InoculateIT) and here is his response:
Hi - I work with Allan Kelly who started this thread. I know next to
nothing about TSM, but am fairly well versed with Windows NT / 2000 / XP
and
I wanted to clear up a misconception I saw here. Specifically, the idea
of
"accessing a file and then resetting the file's access time to it's
original
value".
It's true that the standard file APIs cause the file's access date to be
updated (at least the ones which open an individual file - there are also
directory scanning API functions which return information about files in a
directory such as file names, dates and basic attributes that don't change
the access dates of the individual files). Since most programs use the
standard API functions, most programs update the "last access time" of
files
they touch.
However there's another set of file access API functions specifically
designed for backups and restores. The actual function calls are
"BackupRead" and "BackupWrite". These calls differ from the standard file
system API calls in the following ways:
- They access even "hidden" file info such as security, multiple data
streams, and user-defined attributes.
- They allow access by processes holding the Backup Operator privilege
even
to files that are protected against administrator access.
- They don't update the file's "last accessed" timestamp.
The native NTBackup utility uses these API functions to back up and
restore
files. TSM must use them too, since our tests show that it can back up
files that would otherwise be protected against it.
I'm no designer of virus scanning software, but it seems to me that it
would
make a lot of sense for a virus scanner to use the backup API functions
because it would need to make use of all of the extra functionality that
those functions provide (ie, access to protected files, access to normally
hidden data streams in the file, etc.). Writing a virus scanner that
opens
files using the standard API and then going back and "fixing" the access
dates seems to me like a pretty silly design.
Since TSM appears to use the backup API functions, the question remains as
to why it updates the file access dates. One possibility is that the
dates
are updated on the initial file scan pass when TSM is matching NTFS files
against files in the TSM database to see which files need to be backed up.
If the initial file scan pass opens the input files using the standard
file
API functions then it could explain this behaviour.
Sean Nelson
BC Rail Ltd.
North Vancouver BC
Canada
Thanks for any help.
Allan Kelly.
-----Original Message-----
From: Andrew Raibeck [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, March 27, 2002 2:47 PM
To: [EMAIL PROTECTED]
Subject: Re: Windows NTFS last accessed date set by TSM client
I don't know why it is designed as it is. Perhaps the overhead in a more
granular resolution would affect performance (imagine if several apps were
repeatedly hammering away at the same file over an extended period of
time).
But that is just a guess.
Regards,
Andy
Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Development
Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
Internet e-mail: [EMAIL PROTECTED]
The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.
Alex Paschal <[EMAIL PROTECTED]>
Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 03/27/2002 14:27
Please respond to "ADSM: Dist Stor Manager"
To: [EMAIL PROTECTED]
cc:
Subject: Re: Windows NTFS last accessed date set by TSM
client
Zoinks. What kind of stupid filesystem is that? Back to testing. Thanks
for the info, Andy.
Alex
-----Original Message-----
From: Andrew Raibeck [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, March 27, 2002 12:21 PM
To: [EMAIL PROTECTED]
Subject: Re: Windows NTFS last accessed date set by TSM client
Hi Alex,
I believe that on NTFS, last access time has a resolution of 1 hour. Thus
if
the file was accessed within the last hour, accessing it again won't
change
the last access time. If the file was accessed over an hour ago, then
accessing the file will change the last access time. So in some cases,
yes,
it is possible that if TSM access the file, it won't cause the last access
time to change. It depends on when the file was last accessed prior to the
TSM 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: [EMAIL PROTECTED]
The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.
Alex Paschal <[EMAIL PROTECTED]>
Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 03/27/2002 11:54
Please respond to "ADSM: Dist Stor Manager"
To: [EMAIL PROTECTED]
cc:
Subject: Re: Windows NTFS last accessed date set by TSM
client
Andy,
What exactly is the issue? Personally, during my testing, it looked like
the TSM client maintained the last access date and NTFS didn't
automatically
update the Last Access date as you describe when TSM accessed the file (on
WinNT4 SP6, I think). The updated access time issues I encountered had to
do with interoperability with the McAfee virus scan software. Here is the
message I posted with one of my actual tests copied and pasted in it.
http://msgs.adsm.org/cgi-bin/get/adsm0109/460.html
I believe your statement that NTFS updates the Access Date when TSM access
the file possibly occurs under situations I didn't test. Could you give
us
more detail?
Thanks,
Alex Paschal
Storage Administrator
Freightliner, LLC
(503) 745-6850 phone/vmail
-----Original Message-----
From: Andrew Raibeck [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, March 26, 2002 4:32 PM
To: [EMAIL PROTECTED]
Subject: Re: Windows NTFS last accessed date set by TSM client
This is a known issue, and we are working on a solution.
For what it is worth, TSM does not *actively* change the last access date;
this is a property of how the file system works, that any application that
touches a file will update the last access date. Applications that don't
"change" the last access date are almost certainly implicitly changing it
when they touch the file, but then resetting it when they are done. As I
mentioned above, we are working on resolving this ourselves.
For now, there isn't anything that can really be done about this. However,
TSM should normally only be touching files that have actually changed
(assuming that you do regular incremental backups). If that is the case,
then it can be assumed that if TSM is backing it up, it must have been
changed, and thus accessed by some other application; so it would not be
subject to your purge by last access date rule, anyway.
Regards,
Andy
Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Development
Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
Internet e-mail: [EMAIL PROTECTED]
The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.
Allan Kelly <[EMAIL PROTECTED]>
Sent by: "ADSM: Dist Stor Manager" <[EMAIL PROTECTED]> 03/26/2002 16:20
Please respond to "ADSM: Dist Stor Manager"
To: [EMAIL PROTECTED]
cc:
Subject: Windows NTFS last accessed date set by TSM client
We have a couple of Windows file servers that we back up with the TSM
Windows client 4.1.2.14 to our TSM Windows 4.1.3.0 server. The file last
accessed date is set during the scheduled backup run and we do not know
how
to stop it. We want to run purges based on the last accessed date but we
are stymied.
Any useful suggestion are most urgently needed.
Thanks.
Allan Kelly.
