[OSM-dev] Tirex Bucket Configuration

[Adam Ratcliffe]

Thanks Jochen and Frederik for these tips - that should be plenty to
get me started :)

Cheers
Adam

On Wed, Jun 15, 2011 at 7:33 PM, Jochen Topf <jochen at remote.org> wrote:
> On Wed, Jun 15, 2011 at 06:09:13PM +1200, Adam Ratcliffe wrote:
>> We've been using mod_tile/renderd for approx. a year serving an
>> australasian tile set, we will only be serving this one tile set for
>> the foreseeable future.  We're now looking at rebuilding our tile
>> servers and I have set up a test installation running Tirex.
>>
>> I'm wondering if anybody is able to provide me with any guidelines on
>> how to configure the buckets.  Is there a relationship between the
>> maxproc setting and the number of CPUs available on the host for
>> instance?
>
> All of this of course depends on the details of your hardware, the map data
> you have, the number of tiles, the access pattern etc. But here are some
> points to get you started:
>
> * You probably don't want to have too many rendering processes even if you
>  have many CPUs, because then your bottleneck will be the database disk
>  access.
> * You also, of course, don't want to few rendering processes, because you
>  don't want an idle machine.
> * You should not use all capacities in the low priority buckets, so that
>  there are always capacities available if high priorities come in.
> * For the highest priority bucket, your maxproc should probably be slightly
>  higher than the number of CPUs you have. Slightly higher because some processes
>  will be waiting for IO. Maxload about twice that (1 for the renderer
>  process, 1 one for the datatabase process).
> * For all other buckets use less. Numbers depend on your ratio of interactively
>  rendered tiles vs. background-rendered tiles. If you want snappier access
>  for live rendering give low-priority buckets smaller maxproc/maxload, but
>  background-rendering will be slower.
>
> Start with those ideas and then watch your system and change settings
> accordingly. Look at the jobs.log logfile for rendering times and success
> rate. Experiment with different settings.
>
> Jochen
> --
> Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/  +49-721-388298
>
>