[mapserver-users] MapCache clusters

[Sebastiano Laini]

Is not just the MapCache instances but also MapServer instances included so in theory you have X MapServers accepting request depending on the number of instances.
Making tests today I discover that if we use just Vector and Raster layer I can reach 100 tiles/s in a VM with 8core and 8GB RAM even though the ram is under 1GB of use.
A 4core reach the same speed, and I was using –p 5 and 10 respectively.

Yesterday I came across this article https://www.maptiler.com/blog/2018/04/maps-with-docker.html and I was wondering if was something possible also with MapServer/MapCache.

Again if we use just Vector and Raster I think I can seed in 15 days instead of more than 60 days but is still a lot because I have 4 cache to seed twice a year.

Sebastiano Laini
Web Developer
Buchanan Computing

From: Travis Kirstine [mailto:traviskirstine at gmail.com]
Sent: 19 November 2019 16:11
To: Sebastiano Laini <Sebastiano.Laini at BuchananComputing.co.uk>
Cc: mapserver-users at lists.osgeo.org
Subject: Re: [mapserver-users] MapCache clusters

I don't think multiple instances of MapCache will help for seeding, in general most of the seeding time depends on the zoom level, with each higher zoom level taking 4 x the time as the proceeding zoom level (e.g. zoom 20 take 4 x the time to seed as zoom 19)  .  This can vary depending on your source service as there may be certain map scales / zoom levels that take longer per tile to render due to expression, labels, # of features etc... If you were to seed two levels for each mapcache instance you still would be waiting for the higher zoom levels to complete.   Using multiple load balanced mapserver nodes across multiple VM may improve things a bit however if all the VMs are hosted on the same physical server this may be slower overall.  For seeding I have heard you can use 2x the number of cores so you could set up a single mapcache server using -n 16 pointing at the load balanced source.

Regards



On Mon, 18 Nov 2019 at 10:47, Sebastiano Laini <Sebastiano.Laini at buchanancomputing.co.uk<mailto:Sebastiano.Laini at buchanancomputing.co.uk>> wrote:
Hi All,

I was wondering if is possible to dockerise my server and then use multiple cluster to seed the cache? I know I can use multiple processes with the –n and –p flag though I’m wondering there is a limit on how much you can really increase those number.

E.g. I dockerise the server and I spawn a 8core VM with 16GB ram, I can use sure –p 8 or maybe 10 but still I think that will require like 60 days to seed the whole UK with our data, can I spawn another machine and speed up the process? For example another 8core VM.

We have 4 caches with different style that are updated twice a year so if it takes me 60 days for each by the time I finish it’s already time to start again.

I was wondering maybe I can run multiple VM and seed one or maybe 2 levels on each VM or if I spawn a new VM the original process will take advantage of the new VM?
In a VM I’m going to have MapServer and MapCache and I will use a subdomain under a load balancer just to seed while the domain will be use just for the seeded cache and in the same way will be under a load balancer.

Regards,

Sebastiano Laini
Web Developer
Buchanan Computing
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