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From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
To: Stefan Esser <se@freebsd.org>
Subject: Re: FreeBSD for serious performance?
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> The cause of the low write performance is the disabled write cache.
> Enabling the write cache is unsafe on SATA drives (with or without
> NCQ), since they do not make any guarantees that nearby data is not
> lost if power fails during a disk write. It never happened to me,
> but there is a reason that SAS drives have less capacity, much lower
> BER (one to two magnitudes) and are more expensive than SATA drives.

interface have nothing to do. Both allows you to force writes now and 
then.

> The solution to the performance problem is simple: Turn on the write
> cache. If the data is valuable, then SAS is the solution to both the

If data is valuable, regular and well done backup practice is the only 
solution.

> would pay one developer hour. Asking Nvidia to release the confidential
> documentation for their chip-set might help, but I doubt that there is
> much interest to add support for NCQ to an obsolete chip-set, today,
> unless you pay a developer (and even then ...).

Even without this, i've never seen properly working NVidia hardware. ANY