PostgreSQL alternative to "Oracle Real Application Cluster"

Hello list

I am working with PostgreSQL for the Bavarian Cadastral Administration.
We want to update our WWW online services so that they can use more
data. For that reason we want to set up an archive of geographical data
(ca. 400GB vector data and - maybe also 4 TB of raster data) manily used
for http services, i.e. the focus is on read operations. (although we
have to do also some kind of replication from primary storage ) The
system should be highly performant and highly available. The use is
designed mainly for OpenGIS standardized WWW applications on
geographical data such as UMN MapServer ( > several 100000 web hits for
geographical data alone). Yet it is not quite clear if we put the raster
data simply in a file system or (as BLOBs) into a database.

We use a lot of OpenSource software, not only PostgreSQL. Using
OpenSource software is a major column of our IT strategy.

Now we have got a proposal for hard- and software for this machine which
is based mainly on the concept of the "Oracle Real Application Cluster"
on RedHat Linux boxes & file servers.
The concept is said to offer big performance - but this concept does not
fit into our IT strategy very well. We are a bit cautious concerning
promises, as Oracle Real Application Cluster seems to be some kind of
"black box" and we do not know HOW it really works.

What we would like to have is some alternative concept which allows us
to use PostgreSQL on a powerful hardware to get highly performant and
higly available database access on our terabytes.

a) Does PostgreSQL have some features using a clustered hardware?
b) If no, what could be an alternative hardware concept ?

Can anybody give me some advice or some hints to somebody who could help
us a bit further, some web page ...

Any help will be greatly appreciated.

Thanks a lot.

Yours,

Hubert

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Dr.-Ing. Hubert Fröhlich
Bezirksfinanzdirektion München
Alexandrastr. 3, D-80538 München, GERMANY
Tel. :+49 (0)89 / 2190 - 2980
Fax :+49 (0)89 / 2190 - 2459
hubert(dot)froehlich(at)bvv(dot)bayern(dot)de