Date: Fri, 20 Feb 2009 22:16:08 +0000 From: Dieter <freebsd@sopwith.solgatos.com> To: freebsd-performance@freebsd.org Subject: Re: Extremely slow write speeds to disk : FreeBSD 7.1 and Dell SAS 6/iR Adapter Message-ID: <200902210616.GAA14352@sopwith.solgatos.com> In-Reply-To: Your message of "Thu, 12 Feb 2009 11:57:02 GMT." <49940E8E.1080107@thekeelecentre.com>
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> > But the issue is that writing to disk is extremely slow...i.e. 14Mb per > > second.... > > > > If I install any other linux distribution, like CentOS, write speek is > > the way it should be..it averages around 190Mb+ per second > > > > I was hoping if it were at all possible for you to assist me in with a > > later RAID Controller Driver for the SAS 6/iR Adapter > > Try: > hw.mpt.enable_sata_wc=1 > in /boot/loader.conf and reboot. > > Assuming you are using SATA drives, the write cache is disabled by > default. This reenables it. The mpt manpage holds more information. Just keep in mind that turning the disk's write cache on puts your data at risk. :-( The correct solution is NCQ.
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