Increasing the size of active logs

Sridharan Muthuraman

Increasing the size of active logs

Hi Folks,

Currently i'm planning to increase the size of the active log datasets of one of the DB2 subsystem from 27000 tracks  (1.3 GB) to 87375 tracks (4 GB) to increase the log information retention period (currently just ~16 min during peak). Proportionately, i'm also increasing the size of the archive logs PRIQTY (offloaded to disk) to 87375 tracks to avoid any extents. Is it advisable to set PRIQTY as 65000 tracks (DFSMS limit on single volume) and allow archive log dataset to extend to second volume without any performance impact or space issues? Do i need to move the active log datasets and archive log datasets to volumes of data class with extended addressability enabled and DSNMTYPE as LARGE or EXTENDED REQUIRED?  Please throw some light on the best option.

 

Thanks,

Sridharan

Roy Boxwell

Increasing the size of active logs
(in response to Sridharan Muthuraman)
Hi!

I just wrote a newsletter all about this topic...If you want to read it simply click on the „more” under “News from the labs!” on my firms web site, then click on “newsletter archive” and select 2017-10 “Log size: How big is your LOG?”.
If the site is in German, click on the little GB flag at the top right!

HTH

Roy Boxwell

SOFTWARE ENGINEERING GMBH and SEGUS Inc.
-Product Development-

Heinrichstrasse 83-85
40239 Duesseldorf/Germany
Tel. +49 (0)211 96149-675
Fax +49 (0)211 96149-32
Email: [login to unmask email]<mailto:[login to unmask email]>
http://www.seg.de http://www.seg.de

Software Engineering GmbH
Amtsgericht Düsseldorf, HRB 37894
Geschäftsführung: Gerhard Schubert

From: Sridharan Muthuraman [mailto:[login to unmask email]
Sent: Tuesday, January 2, 2018 10:48 AM
To: [login to unmask email]
Subject: [DB2-L] - Increasing the size of active logs


Hi Folks,

Currently i'm planning to increase the size of the active log datasets of one of the DB2 subsystem from 27000 tracks (1.3 GB) to 87375 tracks (4 GB) to increase the log information retention period (currently just ~16 min during peak). Proportionately, i'm also increasing the size of the archive logs PRIQTY (offloaded to disk) to 87375 tracks to avoid any extents. Is it advisable to set PRIQTY as 65000 tracks (DFSMS limit on single volume) and allow archive log dataset to extend to second volume without any performance impact or space issues? Do i need to move the active log datasets and archive log datasets to volumes of data class with extended addressability enabled and DSNMTYPE as LARGE or EXTENDED REQUIRED? Please throw some light on the best option.



Thanks,

Sridharan

-----End Original Message-----

Sridharan Muthuraman

RE: Increasing the size of active logs
(in response to Roy Boxwell)

Hi Roy,

Thanks for your reply. I have been using your article as my primary reference for this activity :-) . Just wanted to know if we have to move the active log datasets to different data class with extended addressability enabled as the size is larger than 65535 tracks?

Regards,

Sridharan.M

Roy Boxwell

Increasing the size of active logs
(in response to Sridharan Muthuraman)
Yes indeed! The Limit per allocated volume (65535 Tracks) is there for Active as well as Archive logs as it is an allocation (DFSMS) limit. So switching to EXT and IFEXT to R will attempt to allocate your size on one volume (I would not recommend going multi-volume on active logs but I must admit it might not really be too bad these days...)

Roy Boxwell

SOFTWARE ENGINEERING GMBH and SEGUS Inc.
-Product Development-

Heinrichstrasse 83-85
40239 Duesseldorf/Germany
Tel. +49 (0)211 96149-675
Fax +49 (0)211 96149-32
Email: [login to unmask email]<mailto:[login to unmask email]>
http://www.seg.de http://www.seg.de

Software Engineering GmbH
Amtsgericht Düsseldorf, HRB 37894
Geschäftsführung: Gerhard Schubert

From: Sridharan Muthuraman [mailto:[login to unmask email]
Sent: Tuesday, January 2, 2018 11:33 AM
To: [login to unmask email]
Subject: [DB2-L] - RE: Increasing the size of active logs


Hi Roy,

Thanks for your reply. I have been using your article as my primary reference for this activity :-) . Just wanted to know if we have to move the active log datasets to different data class with extended addressability enabled as the size is larger than 65535 tracks?

Regards,

Sridharan.M

-----End Original Message-----

Lizette Koehler

Increasing the size of active logs
(in response to Sridharan Muthuraman)
When increasing the size of any datasets, you should be working with your storage admins. They can help
you with your file sizes and making sure primary dasd is available. And make sure your files are protected for DR as well as
Being able to support storage.

We use dfhsm to migrate the dasd pool where the DB2 logs reside. When the DBAs do research they need more room to recall the logs they need.

Lizette



Sent from EarthLink Mobile mail
On 1/2/18, 3:33 AM, Sridharan Muthuraman <[login to unmask email]> wrote:

From: Sridharan Muthuraman <[login to unmask email]>
To: [login to unmask email]
Subject: [DB2-L] - RE: Increasing the size of active logs
Date: January 2, 2018 at 3:33:12 AM MST
Hi Roy,
Thanks for your reply. I have been using your article as my primary reference for this activity :-) . Just wanted to know if we have to move the active log datasets to different data class with extended addressability enabled as the size is larger than 65535 tracks?
Regards,
Sridharan.M


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Lizette Koehler

Increasing the size of active logs
(in response to Roy Boxwell)
Roy,



If DB2 can handle really large LOG Datasets, then the Storage Admin can setup SMS coding and the EAV volumes that can be greater than 55GB and up to 225GB in Size (I think)



Then if there is sufficient storage in the shop, you could have the storage admin team create the needed EAV Volumes for huge DB2 Logs. Of course the normal caveats.



Backup of LOG Files may be slow. HSM Migration/Recall of the archive logs maybe slow. And various other considerations.



Lizette





From: Boxwell, Roy [mailto:[login to unmask email]
Sent: Tuesday, January 02, 2018 3:47 AM
To: [login to unmask email]
Subject: [DB2-L] - RE: Increasing the size of active logs



Yes indeed! The Limit per allocated volume (65535 Tracks) is there for Active as well as Archive logs as it is an allocation (DFSMS) limit. So switching to EXT and IFEXT to R will attempt to allocate your size on one volume (I would not recommend going multi-volume on active logs but I must admit it might not really be too bad these days...)



Roy Boxwell

SOFTWARE ENGINEERING GMBH and SEGUS Inc.
-Product Development-

Heinrichstrasse 83-85
40239 Duesseldorf/Germany
Tel. +49 (0)211 96149-675
Fax +49 (0)211 96149-32
Email: <mailto:[login to unmask email]> [login to unmask email]
http://www.seg.de http://www.seg.de

Software Engineering GmbH
Amtsgericht Düsseldorf, HRB 37894
Geschäftsführung: Gerhard Schubert



From: Sridharan Muthuraman [mailto:[login to unmask email]
Sent: Tuesday, January 2, 2018 11:33 AM
To: [login to unmask email] <mailto:[login to unmask email]>
Subject: [DB2-L] - RE: Increasing the size of active logs



Hi Roy,

Thanks for your reply. I have been using your article as my primary reference for this activity :-) . Just wanted to know if we have to move the active log datasets to different data class with extended addressability enabled as the size is larger than 65535 tracks?

Regards,

Sridharan.M



-----End Original Message-----



-----End Original Message-----