Messages in this thread | | | Date | Tue, 2 Dec 2003 13:02:42 -0500 | From | Jeff Garzik <> | Subject | Re: libata in 2.4.24? |
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On Tue, Dec 02, 2003 at 11:31:45AM -0500, Greg Stark wrote: > > Mike Fedyk <mfedyk@matchmail.com> 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?
Yes, it does. But it depends on whether or not the host controller supports 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.
If true, this is an IDE driver bug... assuming the drive itself doesn't lie about FLUSH CACHE results (a few do).
> 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.
If the drive lies, there isn't a darned thing we can do about it...
> Do the new SATA drives and controllers provide a solution to this?
If the drive lies, there isn't a darned thing the controller can do about it, either ;-)
Jeff
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