[GraphHopper] Memory requirements

[Peter]

Hi Laurent,

I'll answer for the world wide case (for europe they should be roughly
half sized):

 * for CH e.g. the car profile you need 25GB for import and 18GB for
running it if you use the RAM_STORE option
 * without CH you need 25GB to import several vehicles, running it
requires only ~12GB but every request can require more RAM, see also #104
 * Using bike2 or foot requires roughly 50% more for import and running,
CH preparation takes also 2 to 3 times longer than with car (which is
currently at 2h-2.5h)
 * In my tests SSD drive only slightly improves the import speed which
is roughly at 1 to 1.5h
 * But for enabled elevation SSD is very important, also you need
roughly 5GB more for import.
 * Using the mmap config makes everything a lot slower, I've not tested
it for a recent version. Also the speed still depends of the available
RAM. Using mmap for import can save you a bit RAM but using mmap for
running GraphHopper is only recommended on mobile devices.
 * As long as you use areas which create graphhopper files not bigger
than 2gb than it should be possible on a 32bit Android to still do route
calculation on it.

Does this answer your questions?
Maybe others can throw in their experience if my values are completely
off :) !

Regards,
Peter


On 29.01.2015 22:24, Laurent Bendel wrote:
> Hi all,
> just a general question. What kind of RAM does a server needs to serve routing request on a fairly large map (say Europe) ? and what about the complete planet file ?
> I’m more interested in the amount of RAM, disk space is rather cheap, but does it benefit from a fast drive such as an SSD ?
> I guess it depends whether you use CH or not, It’d be interested to know the difference. And if the memory mapping is used instead of RAM, what are the minimum ? I read an Android device is capable of calculating routes, but probably not for a very big planet file.
>
> Last, does the graph building process require more or less RAM than serving requests ?
>
> Thanks,
> Laurent
>
>
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