[OSM-dev] Planet file space requirements

Frederik Ramm frederik at remote.org
Fri Oct 30 08:44:30 GMT 2009


Hi,

Linden Varley wrote:
> Is there potential to be able to do differential updates on a
> non-slim imported db? Reason I ask is I have plenty of memory, but
> little DB space (SSD) and I would like to do weekly diffs, import
> with osm2pgsql and get a tile expiry list to re-cache changed tiles.

If I were you then I would not bother with diffs - you say you can do a 
full non-slim import in four hours, and my guess is that a weekly diff 
in slim mode will not be much faster.

Simply download the full planet file each week and do a full import. You 
say that your rendering is quite fast, so I would not bother doing 
traditional tile expiry either - just regularly run a "find" on the tile 
cache that deletes everything older than X days. If you do want to 
retain cached images then write a script to go over the planet file, 
check the last-modified date of every node, and expire affected tiles only.

I would be interested to hear more performance data of your setup 
(make/model of SSD, time to import planet, time to apply a daily diff, 
some rendering figures).

Bye
Frederik




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