Difference between LUW and zOS

Kowsalya Kumari

Difference between LUW and zOS

Hi, 

I'm working on an assignment to convert DB2 databases from zOS to LUW. Can someone help me with the below questions.

- any difference between Partition by growth tablespace in LUW and zOS, should be considered while creating from zOS to LUW

- How to verify bufferpool allocation on LUW to ensure it is same as on zOS

- We have partition rotation on zOS, do we need same functionality on LUW

 

Thanks

Kowsalya

Greg Palgrave

RE: Difference between LUW and zOS
(in response to Kowsalya Kumari)

Hi Kowsalya,

I haven't worked on z/OS for a long time, but the transition to LUW is one where you will find a lot of similarities, as well as some notable differences.

Use the online docs - https://www.ibm.com/support/knowledgecenter/en/SSEPGG_11.1.0/com.ibm.db2.luw.container.doc/doc/c0052965.html

First advice - check the LOCKTIMEOUT setting in your db cfg. By default it is set to -1 (no timeout). This will kill you coming from zOS.

There are no ZPARMS, these are the basic places you define your configuration:

  • Database configuration - db cfg
  • Database manager Configuration - dbm cfg
  • Db2 profile registry command - db2set

LUW instance = zOS subsystem (roughly speaking)

LUW database <> zOS databases.  LUW can have multiple databases per instance, but you can't (easily) query across databases. Generally 1 database, many tablespaces, many tables.

LUW can use AUTO memory management (STMM), so you can set your bufferpools to AUTO grow/shrink.This may work well, or it may not suit your workload. You can always set them to a fixed size.

BP info is in SYSCAT.BUFFERPOOLS, but I suggest you also get familiar with db2pd and dsmtop (or db2top) commands (assuming you're on a unix style OS) as well as the SYSIBMADM administrative views/routines. You can also use GET SNAPSHOT commands, but they're ugly :).

LUW can use Table partitioning, and rolling in/out partitions can be done in LUW. The syntax may well vary from zOS, so refer to the docs. I'm not sure about TS partition by growth in LUW though - I think that is zOS only at this stage.

Tablespaces can be defined as MANAGED BY AUTOMATIC STORAGE, and can be set to use AUTORESIZE. Set meaningful values for the INITIALSIZE and INCREASESIZE parameters (don't use PERCENT, you'll regret it) and optionally MAXSIZE if you want to limit the TS size.

Good luck with your mission!

Cheers,

Greg



In Reply to Kowsalya Kumari:

Hi, 

I'm working on an assignment to convert DB2 databases from zOS to LUW. Can someone help me with the below questions.

- any difference between Partition by growth tablespace in LUW and zOS, should be considered while creating from zOS to LUW

- How to verify bufferpool allocation on LUW to ensure it is same as on zOS

- We have partition rotation on zOS, do we need same functionality on LUW

Kowsalya Kumari

RE: Difference between LUW and zOS
(in response to Greg Palgrave)

Thanks Greg, good information for newbies in this area. 

Thanks

Kowsalya

Kay Groski

RE: Difference between LUW and zOS
(in response to Kowsalya Kumari)

In LUW we use Data Server Manager (DSM) to manage, optimize and monitor databases.  Join the IBM HDM Communities such as DSM and Db2 Warehouse. https://community.ibm.com/community/user/hybriddatamanagement/home The DTE site has some great demos to get you started: https://ibm-dte.mybluemix.net/db2-warehouse