500 requests per second

     Hi guys,

     I'm looking for a database+hardware solution which should be able
to handle up to 500 requests per second. The requests will consist in:
     - single row updates in indexed tables (the WHERE clauses will use
the index(es), the updated column(s) will not be indexed);
     - inserts in the same kind of tables;
     - selects with approximately the same WHERE clause as the update
statements will use.
     So nothing very special about these requests, only about the
throughput.

     Can anyone give me an idea about the hardware requirements, type
of
clustering (at postgres level or OS level), and eventually about the OS
(ideally should be Linux) which I could use to get something like this in
place?

     Thanks!

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