Re: [PERFORM] Increasing RAM for more than 4 Gb. using postgresql

[William Yu]

I inferred this from reading up on the compressed vm project. It can be 
higher or lower depending on what devices you have in your system -- 
however, I've read messages from kernel hackers saying Linux is very 
aggressive in reserving memory space for devices because it must be 
allocated at boottime.



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Josh Berkus wrote:
William,

The theshold for using PAE is actually far lower than 4GB. 4GB is the
total memory address space -- split that in half for 2GB for userspace,
2GB for kernel. The OS cache resides in kernel space -- after you take
alway the memory allocation for devices, you're left with a window of
roughly 900MB.

I'm curious, how do you get 1.1GB for memory allocation for devices?
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