ADSM-L

Re: TSM altering Windows access time?

2006-10-30 13:28:00
Subject: Re: TSM altering Windows access time?
From: Andrew Raibeck <storman AT US.IBM DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Mon, 30 Oct 2006 11:27:09 -0700
Access time is not modification time. Access time means the last time
someone touched a file. For example, if you use Windows Explorer to view a
file's properties, the access time will automatically be updated. This is
not something the application does explicitly, but is a function of the
file system.

So the TSM client does not change the modification time; this just happens
implicitly because the client reads the file during backup. In most cases,
it is not an issue (technically speaking), but for HSM-like products, it
can have an impact. Hence the option I mentioned.

> Wait, the docs say that the TSM client will do an "update" on a file if
> the "last access time" is changed between backups.

Can you point me to where this is stated? I don't see it in the client
manual (I'm looking in chapter 4, section "Full and partial incremental
bacukp").

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.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 10/30/2006
11:08:29 AM:

>    So the TSM backup client ~does~ change the last access
> time??!?!? That's not what I have been telling folks....
>
>
> Wait, the docs say that the TSM client will do an "update" on a file if
> the "last access time" is changed between backups. If the TSM client
> itself is changing the last access time, wouldn't that mean that every
> night the TSM server would "update" every file on the host because it is
> changing the last access time every time it runs?
>
>    I've looked around on various hosts and can see there are old
> files that have backups run on them every night but have access times
> that are 4 years old.
>
>    Can you explain a little better the conditions that TSM will
> change the "last access time"?
>
>    Is it updated perhaps every time that the TSM has to actually
> backup the file because it has changed? In that case should I expect to
> see the "modification time" and the "access time" on a changed file be
> up to 1 day apart if the TSM backups run once a day on the host?
>
>
> Thanks,
> Ben
>
>
>
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf 
> Of
> Andrew Raibeck
> Sent: Monday, October 30, 2006 10:47 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: TSM altering Windows access time?
>
> See the PRESERVELASTACCESSDATE client option.
>
> 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.ibm.com/software/sysmgmt/products/support/IBMTivoliStorageMan
> ager.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 10/30/2006
> 10:03:59 AM:
>
> >    I'm being told by various vendors that the TSM backup client on
> > Windows causes problems with their ILM  products, the ones that move
> > older, unaccessed data to cheaper storage.
> >
> >    They are saying that the TSM backup client will alter the last
> > access date, making it look like the file is being access when it's
> > only being backed up.
> >
> >    Has anyone seen this? I'm not sure if they are saying that the TSM
> > client does this on the first full backup or on the subsequent
> > incrementals.
> >
> >    I am going to do some testing to see what I can see, but was
> > wondering if  anyone has seen this behavior...
> >
> > Ben