Date: Thu, 25 Oct 2001 08:48:27 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: Chris Pearce <ferox@paradise.net.nz> Cc: freebsd-questions@freebsd.org Subject: Re: Harddrive reporting wrong RPM Message-ID: <20011025084827.A1152@student.uu.se> In-Reply-To: <01102519212300.00352@Ferox> References: <01102519212300.00352@Ferox>
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On Thu, Oct 25, 2001 at 07:21:23PM +1300, Chris Pearce wrote: > Hey, > > I recently installed FreeBSD4.3, and I noticed my > harddrive seems to be running slower than it has > done under Windoze and Linux. I ran 'disklabel ad0' > and it told me that my rpm of my HD is 3600, which > is wrong; the drives only 9 months old. I think that FreeBSD does not really know anything about how many rpm the disk has. The 3600 I believe is only a default value to be used in case no further information is available. > > If I run 'disklabel -e ad0' and changed the rpm > manually, will it speed up the drive, or could it > damage it instead? (Thought I'd better check before > I tried.....) Neither probably. I don't think the rotational speed of the harddisk can be controlled by software. > > Is there any other ways to speed up the HD, like > doing something funky with DMAs? Turning on write-caching should give a noticable performance boost. This was, by default, turned off in 4.3. To check if write caching is on or off do: sysctl -a | grep ata.wc This should display a line like hw.ata.wc: 0 If it is a "1" instead of "0" then write caching is already turned on. To enable write caching if it is not enabled you will need to add the line hw.ata.wc="1" to the file /boot/loader.conf and then reboot. A warning though: With write caching enabled you run the risk of losing more data or leaving the disk in an inconsistent state if the computer should crash. Search the mailing-list archives for much more discussion on this. -- <Insert your favourite quote here.> Erik Trulsson ertr1013@student.uu.se To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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