Re: libata in 2.4.24?

From: Greg Stark
Date: Tue Dec 02 2003 - 11:33:12 EST



Mike Fedyk <mfedyk@xxxxxxxxxxxxx> writes:

> > Libata, uses the scsi system instead of the existing ide layer because many
> > new sata controllers are using an interface that is very similair to scsi
> > (much like atapi).

Now I have a different question. Does the scsi-like SATA interface include tcq?

Because one of the long-standing issues with IDE drives and Postgres is the
fact that even after issuing an fsync the data may be sitting in the drive's
buffer. This doesn't happen with SCSI because the drives aren't forced to lie
about the data being on disk in order to handle subsequent requests. Turning
off write-caching on IDE drives absolutely destroys performance.

Do the new SATA drives and controllers provide a solution to this?

--
greg

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