DB2 FOR LUW / DB2FORLUW / 970 - DB2

STMM does not make sufficient allowance for system memory 
requirements in two cases: 
- memory which is paged out and only exists in paging space is 
not accounted for, which can result in continually increasing 
tunings if Linux is swapping out memory before DB2 perceives a 
system to be overcommitted 
- large file cache requirements due to a high amount of dirty 
pages.  Dirty file pages cannot be reclaimed until they are 
laundered (written out), and contribute to the level of 
committed memory on a system.  A high volume of dirty pages may 
be triggered by activity on tablespaces with buffered I/O (such 
as sort, reorgs in SMS temporary tablespaces where buffered I/O 
is the default), backups to disk, other. 
 
The lack of accounting for these two cases may contribute to 
swapping on the system.  Note that vm.swappiness should be set 
to 0 on all DB2 system, otherwise swapping may occur on systems 
which are not overcommitted (memory requirements are not 
exceeding RAM).

**************************************************************** 
* USERS AFFECTED:                                              * 
* DB2/Linux systems with self-tuning of Database Memory        * 
* enabled (SELF_TUNING_MEM=ON, DATABASE_MEMORY=AUTOMATIC)      * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 Version 9.7 Fix Pack 5                        * 
****************************************************************

Use DB2_BACKUP_USE_DIO for backups to disk, non-buffered DMS 
temporary tablespaces instead of SMS. 
Ensure vm.swappiness is set to 0.

DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
 

Problem first fixed in DB2 Version 9.7 Fix Pack 5

not known / see Local fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

31.07.2011
29.03.2012
29.03.2012

9.7.FP5