Thursday, August 11, 2011

Tweaking Linux Kernel Overcommit Behaviour for memory

You can change the behaviour of the Linux Kernel in regardings to its Overcommit Behaviour for memory. You can change the behaviour at /etc/sysctl.conf/ or /etc/sysctl.d/myconfig.conf

You will write something like
vm.overcommit_memory = (a integer from 0 to 2)
where
0 - means that the kernel will use predefined heuristics when deciding whether to allow such an overcommit. This is the default.
1 -always overcommits (Very dangerous)
2 - Prevents overcommits from exceeding a certain value. Within this mode, the total commit can not exceed the swap space(s) size + overcommit_ratio percent * RAM size. By default, the overcommit ratio is 50.

For example, do look at Memory Management - Preventing the kernel from dishing out more memory than required





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