Re: Hardware/OS recommendations for large databases (

"Luke Lonergan" <llonergan@greenplum.com> writes:
> OK - slower this time:

> We've seen between 110MB/s and 120MB/s on a wide variety of fast CPU
> machines with fast I/O subsystems that can sustain 250MB/s+ using dd, but
> which all are capped at 120MB/s when doing sequential scans with different
> versions of Postgres.

Luke, sometime it would be nice if you would post your raw evidence
and let other people do their own analysis.  I for one have gotten
tired of reading sweeping generalizations unbacked by any data.

I find the notion of a magic 120MB/s barrier, independent of either
CPU or disk speed, to be pretty dubious to say the least.  I would
like to know exactly what the "wide variety" of data points you
haven't shown us are.

            regards, tom lane