Tuesday, August 30, 2011

ADDR Reports Significant virtual memory paging was detected on the host operating system

Our oracle server is running on Linux x86-64, 24 gb RAM. SGA=10gb
The ADDR Reports on DBConsole displays this message

Significant virtual memory paging was detected on the host operating system.
Host operating system was experiencing significant paging but no particular root cause could be detected.
After searching in metalink, I found that this is expected behavior for windows operating system. But, for 64-bit Linux, SGA>10g tend to cause this problem. Refering to this metalink note HugePages on Oracle Linux 64-bit [ID 361468.1], it says if your combined database SBAs is large (more than 8GB), you will need HugePages configured. But another metalink note "HugePages and Oracle Databaes 11g Automatic Memory Management (AMM) on Linux [ID 749851.1]" discusses the inteoperability of the Automatic Memory Management (AMM) feature introduced by Oracle 11g and the HugePages feature of Linux OS kernel. Whenever 11g AMM feature is enabled by MEMORY_TARGET/MEMORY_MAX_TARGET parameters, HugePages are not used. The use of AMM is absolutely incompatible with HugePages. If you want to use HugePages make sure both MEMORY_TARGET/MEMORY_MAX_TARGET parameter are unset (ALTER SYSTEM RESET)

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