A tragedy caused by the dramatic increase in HugePages ORACLE sessions not enabled, hugepagesoracle

A tragedy caused by the dramatic increase in HugePages ORACLE sessions not enabled, hugepagesoracle

Fault description: HugePages is not enabled in LINUX, the host memory is nearly 300 GB, And the SWAP is 32 GB. The SGA_MAX_SIZE setting of ORACLE is about 80% of the host memory, and the SGA_TARGET setting is about 60% of the host memory. Normally, the database session is about 500. The service changes on the day of the fault, and the number of sessions doubled, reaching the top 1000. The memory is tight and SWAP space is used.

Solution: Change the database time and reconfigure HugePages. After the database is restarted, check that the memory consumption is low, which is an order of magnitude before HugePages is enabled.Hugepage can reduce the cpu burden and reduce the consumption of system memory. In general, we recommend that you configure Hugepage for the linux database system (especially for large memory and many sessions ).

For more information about how to enable and disable hugepages, see http://blog.csdn.net/haibusuanyun/article/details/20697371

About LINUX 6 shutdown; http://blog.csdn.net/haibusuanyun/article/details/41983497

The number of sessions is more than 600
[Oracle @ * ~] $ Ps-ef | grep LOCAL | wc-l
613
[Oracle @ * ~] $ Ps-ef | grep LOCAL | wc-l
647
[Oracle @ ~] $ Free-m
Total used free shared buffers cached
Mem: 257927 255079 2847 0 64 148001
-/+ Buffers/cache: 107013 150914
Swap: 31999 13738 18261
[Oracle @ ~] $ Cat/proc/meminfo | grep PageT
PageTables: 94353044 kB
[Oracle @ ~] $ Free-m
Total used free shared buffers cached
Mem: 257927 255182 2745 0 64 147743
-/+ Buffers/cache: 107373 150553
Swap: 31999 13981 18018
[Oracle @ ~] $ Ps-ef | grep LOCAL | wc-l
654
[Oracle @ ~] $ Cat/proc/meminfo | grep PageT
PageTables: 95038204 kB

When the number of sessions reaches 1000,
[Oracle @ ~] $ Cat/proc/meminfo | grep PageT
PageTables: 110855888 kB
[Oracle @ ~] $ Ps-ef | grep LOCAL | wc-l
1016

Add the usage information after HugePages configuration.

[Oracle @ ~] $ Cat/proc/meminfo | grep Page
PageTables: 164464 kB
[Oracle @ ~] $ Ps-ef | grep LOCAL | wc-l
429