[mapserver-users] What resourse blocks any bigger GeoTIFF output from WCS?

[Lime, Steve D (MNIT)]

Sounds messy... I do like the idea of controlling the use disk storage for scratch files or streaming through configuration.

-----Original Message-----
From: mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Even Rouault
Sent: Wednesday, August 05, 2015 8:03 AM
To: Rahkonen Jukka (MML) <jukka.rahkonen at maanmittauslaitos.fi>
Cc: mapserver-users at lists.osgeo.org
Subject: Re: [mapserver-users] What resourse blocks any bigger GeoTIFF output from WCS?

On Wednesday 05 August 2015 12:48:53 Rahkonen Jukka wrote:
> Even Rouault wrote:
> > On Wednesday 05 August 2015 12:16:49 Rahkonen Jukka wrote:
> >> Hi,
> >> 
> >> Thank you very much about the information. How much about the troubles
> >> remain if 64-bit system is used,
> > 
> > With a 64 bit system, you would still need to be able to allocate 3 times
> > the size of the output file, either from RAM only or RAM + swap space.
> Doesn't it mean that if WCS server happens to get lots of users who would
> make for example 500 MB requests on average  the result could be huge RAM
> usage, lots of swapping and perhaps not so good service level?

Yes. Ideally if there are requests being processed consuming a lot of RAM, new 
big requests should be put in standbye until the RAM usage decreases, but I'm 
not sure how that can be addressed. Perhaps that HTTP servers have options to 
do things like that (they cannot know how much RAM a new request will consume 
for sure, so the best they could do would be to standbye all new requests). 
Wondering if MapServer itself couldn't do that (it could evaluate the memory 
needed for the current request and check the RAM usage), but not sure it is 
really its business.

> 
> -Jukka-

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