Date: Wed, 12 Dec 2012 23:26:16 +0100 (CET) From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> To: Stefan Esser <se@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: FreeBSD for serious performance? Message-ID: <alpine.BSF.2.00.1212122324230.1449@wojtek.tensor.gdynia.pl> In-Reply-To: <50C889D3.1050404@freebsd.org> References: <20121211204323.310760@gmx.com> <CAJ-Vmok-DtKwNW2DJ21E_UBcf%2B3CWHJ0Z8FyiNC=mycKUFNuBA@mail.gmail.com> <50C889D3.1050404@freebsd.org>
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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
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