maximum mmap()

[John Baldwin]

On Wednesday 13 May 2009 7:10:29 am dikshie wrote:
> Hi,
> i found that my rrdtool does not work with mmap() with rra files size
> more than 2GB.
> my question: on i386 arch,  what's maximum size of file to be able to mmap() ?
> do i have to change from i386 to amd64? or added 4GB RAM?

The amount of RAM is not the issue, it is the size of the virtual address
space.  You can lower maxdsiz on i386 to leave more room for mmap, and you
can also change KVA_PAGES in the kernel to leave more address space for
userland than for the kernel perhaps, but you won't get a whole lot more
space that way (you might be able to map 2.5GB or so).  Moving to amd64 gives
you a 64-bit virtual address space and you will be able to easily mmap()
much, much more than 4GB out of the box.

-- 
John Baldwin