AW: [Mapserver-users] Mapserver/ArcIMS: server requirements

[Arnulf Christl (CCGIS)]

Hi,
our experience is limited to customers with about 500,000 to 750,000
requests per month(!!!) which (we believe...) is quite a lot, considering
that one request takes between 0.2 up to 3 seconds server time. The services
in question (all running as WMS) contain between 10 and 70 layers, the
"largest" vector layers (in terms of quantity of elements) can contain up to
500,000 polygon objects (buildings).
Our experience is that any services with dynamic online maps need a lot more
server power than what a standard webserver needs (or provides). It is no
problem to get an internet server capable to answer several million
standard(!) html requests per day, but as soon as dynamic maps are requested
the performance will go down considerably. This is what a lot of internet
engineers tend to ignore!
Therefore we separate the GIS engine from the webserver and cluster the gis
engines until we have enough overall power. This also helps to increase the
stability of the entire system as it is not problem to take one gis engine
out of the cluster and replace it with another staying online all the time.

We have several different web map servers online (ArcIMS, deegree,
SICAD/SD-IMS, MapServer). We believe that it is probably impossible to
compare the different servers which are currently in use because of the
differing contents of the maps. I do not know of any THE STANDARD MAP which
would be necessary to be able to compare.

Then again there exist several optimized services, one service provides 1000
GB of raster data in almost no time but cannot handle vector formats,
another performs the other way round. Therefore in large projects we usually
have to combine several different services in a cascading WMS (which by
itself already slows performace considerably) but in effect we then obtain
best overall results.

Last but not least there are endless tuning options starting from the
network itself, db indexing, data thinning, clustering, etc.

One of our customer who uses both MapServer and ArcIMS gets better results
using MapServer with shape files but again this is probably also a tuning
question (we set up the MapServer environment, another company does the
ArcIMS stuff... and obviously we are better ;-)). The online time of
MapServer lies at 98% compared to a meager 75% in the ArcIMS environment,
which we attribute to the complexity and missing transparency of the second
software package.

Some time ago we have set up a robot environment for testing purposes to get
"real results" with "real data". I do not know if anything like that already
exitsts for MapServer? It would probaly produce the best results to your
answer, but obviously involves settings up the complete service with both
software packages.

Regards, Arnulf.


-----Ursprüngliche Nachricht-----
Von: mapserver-users-admin@lists.gis.umn.edu
[mailto:mapserver-users-admin@lists.gis.umn.edu]Im Auftrag von Justin
Garre
Gesendet: Freitag, 2. Mai 2003 09:09
An: mapserver-users@lists.gis.umn.edu
Betreff: [Mapserver-users] Mapserver/ArcIMS: server requirements


I am trying to get an idea of how many servers/server space will be required
to run Mapserver with a specific number of hits per day.  For example, would
a single server be adequate for 200,00 user sessions per day?  How many
servers would be necessary for 1,000,000 users (site hits) per day?

Granted this questions depends on a variety of criteria such as the
capabilities of the hardware and how large the map files are, but if anybody
would be willing to share what kind of server setup you have and how much
usage you experience on a daily basis it would be greatly appreciated.

Also, would ArcIMS be more demanding than Mapserver in terms of server
consumption?  ie- I understand Mapserver has a more concise code so I am
curious to know if it would be less demanding on our server(s).

Thanks in advance,

Justin Garre
University of Washington
garre_gis@hotmail.com







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