AIX: Paging Space Growth May Occur Unexpectedly With 64K (medium) Pages Enabled (Doc ID 1088076.1)

Last updated on AUGUST 24, 2015

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.1 to 11.2.0.1.0 [Release 10.2 to 11.2]
IBM AIX on POWER Systems (64-bit)

Symptoms

Unexpected growth in paging space utilization may occur on AIX systems running database applications (including Oracle RDBMS), even where sufficient memory exists to keep the application (Oracle) memory in RAM. This may be observed on AIX systems using medium (64K) memory pages. While the performance effects from the paging itself should be negligible, paging space may become exhausted over time. This condition typically results in an outage (eg. system hang, terminated applications).  In an Oracle RAC environment, this may result in a Node being evicted from the cluster.

This problem affects systems running


Note that 64k Pages are the default page size with most later versions of AIX. Oracle will use 64k Pages if the OS is configured for that, and therefore, Oracle systems are prone to this problem. 

Cause

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