[OSM-dev] osm2pgsql slim mode, postgis, and hard disk spindles

[Lennard]

Frederik Ramm wrote:

>     has anyone experimented with different PostGIS setups on a machine 
> that runs osm2pgsql with minutely or hourly "slim mode" updates and has 
> multiple (in my case only 2) hard disks?

I'm doing minute updates on a machine with 3 disks, so I'm interested in 
tweaks that can be done to make full imports go faster. In my experience 
the minute updates go in very fast, but I'm only running an extract, and 
have also applied a bbox parameter to the osm2pgsql diff cmds.

> The first thing people often do to optimise performance is they put 
> indexes on one disk and data on another.

At the moment, I only have pg_xlog on another disk. I did notice some 
speedup after I did that, but I didn't do a benchmark before and after. 
It does seem to import more steadily.

> But given the way osm2pgsql works in "slim" mode, I wonder whether it 
> might perhaps make sense to put the node/way/relation tables on one hard 
> disk, and the tables with geometries (planetosm_line etc.) on the other?

Given that, AFAIK, all tables/indexes are in 1 directory, how will you 
make that distinction?


-- 
Lennard