|
Problem IC61371
|
Status: Closed |
DB2 ON LINUX NEEDS UPDATED OVERRIDE SETTINGS OF KERNEL TUNABLES |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
DB2 overrides certain kernel tunables in startup to try to
ensure smooth operation of the DB2 Database Server. This avoids
putting the burden of tuning the kernel on DB2/Linux
administrators.
Many default limits are too low for DB2's requirements, and some
limits are unnecessary, especially given the difficulty of
finding some correct range/value based on peak workload (which
may change in the future). The Linux kernel itself alters it's
approach to default settings at different levels (one example is
shmall, the total shared memory limit, which is now set so high
by default that it can be considered virtually unlimited).
.
DB2's current strategy for overriding kernel limits is not based
on the size of machines. As a result, as machines have gotten
larger, the override values (eg. shmmax, shmall, kernel.sem) are
not larger enough to prevent unnecessary errors for DB2
installations. In addition, in some configurations DB2 version
9.5 may require a larger virtual shared memory space (not "real"
memory), resulting in a larger shmall requirement.
.
This APAR will both update the override values to take into
account larger machines AND update the standard DB2
documentation, which currently does not state that DB2 overrides
default/low settings. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All DB2 on Linux systems *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* If running on older DB2 levels, it is recommended tomanually *
* set kernel parameter settings to the updatedvalues.This is *
* especially important for new installations on largersystems *
* (eg. 16GB RAM or higher) or where increasingworkload. *
**************************************************************** |
| Local Fix: |
Update kernel tunables manually.
See current documentation for recommendations. |
| available fix packs: |
DB2 Version 9.7 Fix Pack 2 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
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 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
Problem First Fixed in DB2 Version 9.7 Fix Pack 2 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 03.06.2009
14.06.2010
15.07.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP2
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.2
|
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