AIX:ASM will not start after implementing large pages

(Doc ID 2084723.1)

Last updated on MARCH 20, 2018

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 11.2 to 12.1]
IBM AIX on POWER Systems (64-bit)
This note covers the non-AME(IBM AIX OS memory setting) implementation of 16MB large pages in AIX for ASM. AIX 6.1 and 7.1 support setting of three or four page sizes(depending on hardware) -- 4KB, 64KB, 16MB, 16GB. Note that Oracle 11.2+ will automatically use 64KB pages unless AME is enabled at the OS tier. AIX 5.3 was different in many OS tuneables than 6.1+ so this note should not be considered complete for AIX 5.3.(there will be other tuneables)


ASM is not using large pages.ASM will not startup after implementation of large pages / Grid Infrastructure startup fails after implementation of large pages.

ASM alert log shows ASM crashing and memory_target defaulting to a value though it is not set:

Starting ORACLE instance (normal)
System parameters with non-default values:
sga_max_size = 4G
lock_sga = FALSE
large_pool_size = 16M
instance_type = "asm"
sga_target = 3536M
Mon Nov 02 14:01:09 2015
Instance shutdown complete

<parameter changes here>

Mon Nov 02 14:02:39 2015
MEMORY_TARGET defaulting to 3925868544.
Starting ORACLE instance (normal)
Mon Nov 02 14:03:01 2015
MEMORY_TARGET defaulting to 3925868544.
Starting ORACLE instance (normal)


Attempt to disable memory management via setting both memory_target=0 and memory_max_target=0, OHASD log will show the following startup errors:

2015-11-02 14:02:45.210: [ CRSPE][6940]{0:0:2} Got agent-specific msg: CRS-5017: The resource action "ora.asm start" encountered the following error:ORA-00847: MEMORY_TARGET/MEMORY_MAX_TARGET and LOCK_SGA cannot be set together. For details refer to "(:CLSN00107:)" in "/oracle/crs/app/product/11204/log/<node1>/agent/ohasd/oraagent_grid//oraagent_grid.log".


Implemented 16MB pages via the IBM document(IBM_AIX_and_Oracle_DB_Performance_Considerations_03_12_2015.pdf)

AIX parameters to enable pinned memory and 16 MB large pages:

AIX Capabilities required to allow Oracle to use 16 MB large pages (implement as root):chuser capabilities=CAP_BYPASS_RAC_VMM,CAP_PROPAGATE oracle.Followed IBM AIX document quote "AMM can be used with pinned 16 MB pages, provided the formula for calculating the number of large pages (above) is modified to number of large pages=memory_max_target+1."


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