4 GB active log and BLOB logging

JH

4 GB active log and BLOB logging
We are at DB2 V8 NFM, We have 36 800mb active
logs(total 72 dual logging). We like to know the pros
and cons of enlarging our active logs to 4gb (DB2 V8
limit)?


Also, One of our vendor product have LOG=YES turned
on for BLOB tablespaces. Could that be an innocent
mistake by the vendor? Since blob data are static,
I don't see any reason to log them. Need your
advice.

Thanks


____________________________________________________________________________________
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms

Lance D Ziegler1

Re: 4 GB active log and BLOB logging
(in response to JH)

Joe,
How are you archiving those active log partitions?  Do you archive to disk, tape, virtual tape, etc? American Express made the following annotations on Wed Jan 02 2008 14:27:24 ------------------------------------------------------------------------------ "This message and any attachments are solely for the intended recipient and may contain confidential or privileged information. If you are not the intended recipient, any disclosure, copying, use, or distribution of the information included in this message and any attachments is prohibited. If you have received this communication in error, please notify us by reply e-mail and immediately and permanently delete this message and any attachments. Thank you." American Express a ajouté le commentaire suivant le Wed Jan 02 2008 14:27:24 Ce courrier et toute pièce jointe qu'il contient sont réservés au seul destinataire indiqué et peuvent renfermer des renseignements confidentiels et privilégiés. Si vous n'êtes pas le destinataire prévu, toute divulgation, duplication, utilisation ou distribution du courrier ou de toute pièce jointe est interdite. Si vous avez reçu cette communication par erreur, veuillez nous en aviser par courrier et détruire immédiatement le courrier et les pièces jointes. Merci. ****************************************************************************** -------------------------------------------------------------------------------
The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at www.idug.org under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more.
If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services

JH

Re: 4 GB active log and BLOB logging
(in response to Lance D Ziegler1)
archlog1 to virtual tape, archlog2 to tape

--- Lance D Ziegler1 <[login to unmask email]>
wrote:


---------------------------------

Joe,
How are you archiving those active logpartitions? Do
you archive to disk, tape, virtual tape, etc?American
Express made the following annotations on Wed Jan 02
2008
14:27:24------------------------------------------------------------------------------"This
message and any attachments are solely for the
intended recipient and may contain confidential or
privileged information. If you are not the intended
recipient, any disclosure, copying, use, or
distribution of the information included in this
message and any attachments is prohibited. If you have
received this communication in error, please notify us
by reply e-mail and immediately and permanently delete
this message and any attachments. Thank you."American
Express a ajouté le commentaire suivant le Wed Jan 02
2008 14:27:24Ce courrier et toute pièce jointe qu'il
contient sont réservés au seul destinataire indiqué et
peuvent renfermer des renseignements confidentiels et
privilégiés. Si vous n'êtes pas le destinataire prévu,
toute divulgation, duplication, utilisation ou
distribution du courrier ou de toute pièce jointe est
interdite. Si vous avez reçu cette communication par
erreur, veuillez nous en aviser par courrier et
détruire immédiatement le courrier et les pièces
jointes. Merci.
******************************************************************************-------------------------------------------------------------------------------
The IDUG DB2-L Listserv is only part of your
membership in IDUG. DB2-L list archives, the FAQ, and
delivery preferences are at www.idug.org under the
Listserv tab. While at the site, you can also access
the IDUG Online Learning Center, Tech Library and Code
Place, see the latest IDUG conference information,
and much more.
If you have not yet signed up for Basic Membership in
IDUG, available at no cost, click on Member Services



____________________________________________________________________________________
Never miss a thing. Make Yahoo your home page.
http://www.yahoo.com/r/hs

The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms

William Favero

Re: 4 GB active log and BLOB logging
(in response to JH)
Just a reminder that writing the archive log to virtual tape is the same
to DB2 as writing it to real tape. It is NOT the same as writing to
disk so everything is still single thread.

http://blogs.ittoolbox.com/database/db2zos/archives/db2-archive-log-datasets-8282

Like I said.. just a little extra information but nothing really to do
with your question...

Willie

Joe wrote:
> archlog1 to virtual tape, archlog2 to tape
>
> --- Lance D Ziegler1 <[login to unmask email]>
> wrote:
>
>
> ---------------------------------
>
> Joe,
> How are you archiving those active logpartitions? Do
> you archive to disk, tape, virtual tape, etc?American
> Express made the following annotations on Wed Jan 02
> 2008
> 14:27:24------------------------------------------------------------------------------"This
> message and any attachments are solely for the
> intended recipient and may contain confidential or
> privileged information. If you are not the intended
> recipient, any disclosure, copying, use, or
> distribution of the information included in this
> message and any attachments is prohibited. If you have
> received this communication in error, please notify us
> by reply e-mail and immediately and permanently delete
> this message and any attachments. Thank you."American
> Express a ajouté le commentaire suivant le Wed Jan 02
> 2008 14:27:24Ce courrier et toute pièce jointe qu'il
> contient sont réservés au seul destinataire indiqué et
> peuvent renfermer des renseignements confidentiels et
> privilégiés. Si vous n'êtes pas le destinataire prévu,
> toute divulgation, duplication, utilisation ou
> distribution du courrier ou de toute pièce jointe est
> interdite. Si vous avez reçu cette communication par
> erreur, veuillez nous en aviser par courrier et
> détruire immédiatement le courrier et les pièces
> jointes. Merci.
> ******************************************************************************-------------------------------------------------------------------------------
> The IDUG DB2-L Listserv is only part of your
> membership in IDUG. DB2-L list archives, the FAQ, and
> delivery preferences are at www.idug.org under the
> Listserv tab. While at the site, you can also access
> the IDUG Online Learning Center, Tech Library and Code
> Place, see the latest IDUG conference information,
> and much more.
> If you have not yet signed up for Basic Membership in
> IDUG, available at no cost, click on Member Services
>
>
>
> ____________________________________________________________________________________
> Never miss a thing. Make Yahoo your home page.
> http://www.yahoo.com/r/hs
>
> The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms
>
>
>

--
Willie
My DB2 blog --> http://blogs.ittoolbox.com/database/db2zos
Houston, TX, USA

The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms

Max Scarpa

Re: 4 GB active log and BLOB logging
(in response to William Favero)

Logs, in my opinion, should be 'sized' according your recovery needs
(actually for application recover. Disks now break very rarely and if it
happens in most cases it's a microcode error and you lose many disks in one
shot....) so mainly for rollbacks, DB2 restarts and some other things.
If you're filling your logs quickly you can resize them to contain a
significant workload period (ie production from 9.00 am to 5.00 pm or night
workload). Put them directly to 4 GB without a good reason could be a
waste of space (if all 36). See for instance:

DB2 Information Management Technical Conference : Z29 DB2 Logging: Past,
Present, and Future

Here it's stated what W. Favero said about VTS, it can be a serious
bottleneck.

About LOB. I'm fighting hard about LOB in V7, it come out day by day that
they are real hard to manage (even in V8 I'm afraid) and still full of
problems. One reason is logging. Here we have NOT LOGGED to avoid logging
overhead that could be high. But this MUST be decided with application
developers and it could lead to a high frequency of backup. Anyway default
is YES so it could be a vendor's 'mistake' .

Just some consideration

Max Scarpa


The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms

James Campbell

Re: 4 GB active log and BLOB logging
(in response to Max Scarpa)
"blob data are static" means you never insert or delete any blob data.

Correct? Then it doesn't matter, because there will never be any data to log.

If not, it depends on whether you want to be able to recover that inserted data.

James Campbell

On 2 Jan 2008 at 13:17, Joe wrote:

<snip>

> Also, One of our vendor product have LOG=YES turned
> on for BLOB tablespaces. Could that be an innocent
> mistake by the vendor? Since blob data are static,
> I don't see any reason to log them. Need your
> advice.
>
> Thanks
>

The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms

Avram Friedman

Re: 4 GB active log and BLOB logging
(in response to James Campbell)
Besides inserted data / deleted data there is also the issue of updated /
replaced.

There are Three sets of risks associated with LOG NO on LOBS

1) Application and or DB2 failure
2) DASD Loss
3) Datacenter Loss

For case 1 note that LOG NO does not mean do not log anything ... Check
the SQL reference, lots of the activity still gets logged to support back out.
What happens in the case of LOG NO is the 'new' LOB column instance gets
invalidated and is never used again. All the indes and page maps are
adjusted. Ofcourese if there was an 'old' LOB instance it is still there after
backout and the lob sequence number in the base table column points to it.

For case 2 the AUX TS would be recovered to the last image copy by the DBA
and the table spaces used by the base table would be recovered to a point in
time equal to the last AUX copy ... this is an application design issue.
Applications need to tolerate the recovery process.

Case 3 is almost identical to case 2 except it is subject to the sets of last
image copies and logs available at the DR site.

It is worth while to note that for LOB sizes of 1G or more in V8 LOG NO is
forced ... no choice.

There is a historical lesson that may be useful as well ... Prior to DB2 LOBs
there was document and object support for DB2 for OS. It was delivered in a
different IBM product called OAM (Object Access Management). OAM is still
alive and well but its most common use has always been tape support for IBMs
ATLs ... but that is not what it was designed for (Hint look at the name of the
product) It was designed for document storage usually on Optical Write Once
Disk. It used DB2 for Object management. OAM for object management
worked (It did have a few disadvantages like being S L O W due to the optical
disk) It worked with out logging objects.

Best Wishes
Avram Friedman

On Thu, 3 Jan 2008 21:55:35 +1100, [login to unmask email] wrote:

>"blob data are static" means you never insert or delete any blob data.
>
>Correct? Then it doesn't matter, because there will never be any data to log.
>
>If not, it depends on whether you want to be able to recover that inserted
data.
>
>James Campbell
>
>On 2 Jan 2008 at 13:17, Joe wrote:
>
><snip>
>
>> Also, One of our vendor product have LOG=YES turned
>> on for BLOB tablespaces. Could that be an innocent
>> mistake by the vendor? Since blob data are static,
>> I don't see any reason to log them. Need your
>> advice.
>>
>> Thanks
>>
>
>The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list
archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug
under the Listserv tab. While at the site, you can also access the IDUG
Online Learning Center, Tech Library and Code Place, see the latest IDUG
conference information, and much more. If you have not yet signed up for
Basic Membership in IDUG, available at no cost, click on Member Services at
http://www.idug.org/lsms

The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms

Lance D Ziegler1

Re: 4 GB active log and BLOB logging
(in response to Avram Friedman)

Joe,
Is your rate of logging so high that the increased size of the active log partition will hurt you at archive time (elongated archive log offload process)?  If you are restructuring your logging configuration, this is also a good time to see if VSAM striping will help you based upon your disk hardware.   American Express made the following annotations on Thu Jan 03 2008 12:09:33 ------------------------------------------------------------------------------ "This message and any attachments are solely for the intended recipient and may contain confidential or privileged information. If you are not the intended recipient, any disclosure, copying, use, or distribution of the information included in this message and any attachments is prohibited. If you have received this communication in error, please notify us by reply e-mail and immediately and permanently delete this message and any attachments. Thank you." American Express a ajouté le commentaire suivant le Thu Jan 03 2008 12:09:33 Ce courrier et toute pièce jointe qu'il contient sont réservés au seul destinataire indiqué et peuvent renfermer des renseignements confidentiels et privilégiés. Si vous n'êtes pas le destinataire prévu, toute divulgation, duplication, utilisation ou distribution du courrier ou de toute pièce jointe est interdite. Si vous avez reçu cette communication par erreur, veuillez nous en aviser par courrier et détruire immédiatement le courrier et les pièces jointes. Merci. ****************************************************************************** -------------------------------------------------------------------------------
The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at www.idug.org under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more.
If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services