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From: <carlosreimer@terra.com.br>
To: "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: <pgsql-performance@postgresql.org>
Subject: RES: Initial database loading and IDE x SCSI
Date: Fri, 2 Jun 2006 16:54:50 -0300
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> <carlosreimer@terra.com.br> writes:
> > I would like to know if my supposition is right.
>
> > Considering an environment with only one hard disk attached to
> a server, an
> > initial loading of the database probably is much faster using an IDE/ATA
> > interface with write-back on than using an SCSI interface.
> That´s because of
> > the SCSI command interface overhead.
>
> I *seriously* doubt that.
>
> If you see a difference in practice it's likely got more to do with the
> SCSI drive not lying about write-complete ...
>

Many thanks for the answers! There are some more thinks I could not
understand about this issue?

I was considering it but if you have a lot of writes operations, will not
the disk cache full quickly?

If it´s full will not the system wait until something could be write to the
disk surface?

If you have almost all the time the cache full will it not useless?

Should not, in this scenary, with almost all the time the cache full, IDE
and SCSI write operations have almost the same performance?

Thanks in advance,

Reimer