ADSM-L

Re: [ADSM-L] Journaling database retaining upon reboot?

2008-07-11 16:12:25
Subject: Re: [ADSM-L] Journaling database retaining upon reboot?
From: Alex Paschal <apaschal AT MSIINET DOT COM>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Fri, 11 Jul 2008 15:10:56 -0500
Oh, I wish I could take credit for out-of-box thinking, but I got the
idea from DB2 Datalinks which fails writes if DB2 is down.  It's another
example of a database that has to be synchronized with a filesystem.

Have fun!
Alex

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Andrew Raibeck
Sent: Thursday, July 10, 2008 5:06 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] Journaling database retaining upon reboot?

Hi Alex,

Good out-of-the-box thinking, but the drawbacks are probably more severe
than the advantages:

- The TSM journal service (at least on Windows) is not a filter driver.

- Such a solution would cause lots of problems for the OS itself.

- I wouldn't want to be in your shoes if you installed a product that
could cause application failures just to satisfy the journal service.
:-)

Best regards,

Andy

Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Product Development
Level 3 Team Lead
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 07/09/2008
10:29:48 AM:

> Hi, Andy.
>
> Maybe add an option to the journal service setup that could have the
> filesystem filter driver fail writes to the filesystem if the journal
> service is down?  Of course, this would have the obvious serious
> drawback, but maybe in some horrendously large filecount environments
> users might decide it's worth it to enforce journal db/filesystem
> synchronization.
>
>
> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf
Of
> Andrew Raibeck
> Sent: Wednesday, July 09, 2008 9:42 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: [ADSM-L] Journaling database retaining upon reboot?
>
> > Sooo...with all of these issues with jbb, are they being worked
> > on/fine-tuned?
>
> Yes and no.
>
> For the case where you use PreserveDbOnExit=1 and the journal service
is
>
> shut down for some period of time, the behavior will remain unchanged.
> Use
> at your own risk. If the journal service is down, it cannot
effectively
> monitor file system changes so there is no known solution for this.
>
> For the journal corruption issue, we are currently targeting an
> enhancement that allows the journal service to know whether the
database
>
> was closed cleanly (by a clean journal service shutdown). Upon
restart,
> if
> the journal service does not detect the "I was closed cleanly" flag in
> the
> journal database, it will effectively ignore PreserveDbOnExit=1 and
> reset
> the journal database, as if PreserveDbOnExit=0 was in effect. This
would
>
> be in a future release of the product. Note that this does not
represent
> a
> formal announcement or commitment, so this is subject to change.
>
> A THEORETICALLY cleaner solution could include implementation of of a
> journal database with transactional capabilities, including rollback,
> more
> thorough structural integrity checking, etc. Even in a rollback
> scenario,
> in-flight file system changes would be lost (like the case where you
use
>
> PreserveDbOnExit=1 and journal service is down for some period of
time),
>
> leaving a less than perfect solution. But this is all hypothetical,
and
> there are no plans in place.
>
> Best regards,
>
> Andy
>
> Andy Raibeck
> IBM Software Group
> Tivoli Storage Manager Client Product Development
> Level 3 Team Lead
> 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.
>
>
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> Thank you.

This message (including any attachments) is intended only for
the use of the individual or entity to which it is addressed and
may contain information that is non-public, proprietary,
privileged, confidential, and exempt from disclosure under
applicable law or may constitute as attorney work product.
If you are not the intended recipient, you are hereby notified
that any use, dissemination, distribution, or copying of this
communication is strictly prohibited. If you have received this
communication in error, notify us immediately by telephone and
(i) destroy this message if a facsimile or (ii) delete this message
immediately if this is an electronic communication.

Thank you.

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