It would be helpful if snapdiff backups updated the BACKUP_START field, even if 
we have to resign ourselves to nothing recorded as BACKUP_END.
Is there a reason why that can't be done?
- Margaret Clark

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
Pete Tanenhaus
Sent: Tuesday, February 14, 2012 10:09 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Need some support for snapdiff RFE's

Actually this really isn't correct, a snapshot differential backup will detect 
deleted files and will expire them on the TSM server.

Periodic full progressive incremental backups are recommended because "less 
complete" backups such as snapdiff, incremental by date, and JBB can never be 
as comprehensive as a full progressive given that a full progressive examines 
every file on the local file system and every file in the TSM server inventory.

Note that "less complete" implies that changes processed by a full progressive 
might be missed by other "less complete"
backup methods, and this is the reasoning behind recommending periodic full 
progressive incrementals.

JBB is somewhat better in that in makes every attempt to detect conditions 
which indicate that the change journal is out of sync with what has previously 
been backed up and to automatically force the full progressive incremental 
backup instead of requiring the user to manually schedule it.

For reasons that require a very detailed explanation (let me know if you are 
interested), the current snapdiff implementation doesn't have the robustness or 
resiliency that JBB does and therefore really requires manually scheduling full 
progressive incremental backups via the CreateNewBase option.

Hope this helps ...

Pete Tanenhaus
Tivoli Storage Manager Client Development
email: tanenhau AT us.ibm DOT com
tieline: 320.8778, external: 607.754.4213

"Those who refuse to challenge authority are condemned to conform to it"


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  |Paul Zarnowski <psz1 AT CORNELL DOT EDU>                                     
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  |ADSM-L AT vm.marist DOT edu                                                  
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  |02/14/2012 07:12 AM                                                          
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  |Re: Need some support for snapdiff RFE's                                     
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Grant,

The time stamps are not updated, because a snapdiff incremental does not 
deactivate deleted files.  You need to do periodic 'createnewbase' to do this, 
which walks the file system and updates the time stamps.

..Paul

On Feb 14, 2012, at 12:32 AM, "Grant Street" <grants AT AL.COM DOT AU> wrote:

> Hello
>
> Just thought I would plug two snapdiff RFE's(Request For Enhancement) 
> that I created on the IBM developer works site.
>
> I am trying to garner some support for these in the hope that they 
> will be implemented in the future.
>
> I have seen that some of you have had experience with Netapp snapdiff 
> backups and you may have similar beliefs.
>
> "Define snapdiff and other snap options on a per filesystem basis 
> rather than per backup command"
> When running an incremental backup be able to define the snapdiff or 
> other snap option on a per filesystem basis rather than for the whole 
> backup incremental job.
>
>
http://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=12858
>
> "Snapdiff to update last backup fields in filespace data"
> Could you please update the TSM snapdiff client to update the 
> lastbackup information of filespaces when a "query filespace f=d" is 
> issued. This would be the obvious behaviour and would be inline with 
> the documented meaning of the columns
>
>
http://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=13145
>
> TIA
>
> Grant