Date: Tue, 18 Dec 2012 10:23:51 +1100 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: Dieter BSD <dieterbsd@engineer.com> Cc: freebsd-fs@freebsd.org, freebsd-performance@freebsd.org Subject: Re: FFS - Still using rotational delay with modern disks? Message-ID: <20121217232351.GB26067@eureka.lemis.com> In-Reply-To: <20121217214413.263570@gmx.com> References: <20121217214413.263570@gmx.com>
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--tjCHc7DPkfUGtrlw Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Monday, 17 December 2012 at 16:44:11 -0500, Dieter BSD wrote: > The newfs man page says: > > -a maxcontig > Specify the maximum number of contiguous blocks that will be laid > out before forcing a rotational delay. =A0The default value is 16. > See tunefs(8) for more details on how to set this option. > > Is this still a good idea with modern drives where the number of > sectors per track varies, and no one but the manufacturer knows how > many sectors a particular track has? No. It looks as if this, and also a number of comments in sys/ufs/ffs/fs.h and sys/ufs/ffs/ffs_alloc.c, are leftovers from the Olden Days. The value isn't used anywhere that I can see. Unless somebody can show that I'm wrong, I'd suggest that this is a documentation issue that I can take a look at. Greg -- Sent from my desktop computer. Finger grog@FreeBSD.org for PGP public key. See complete headers for address and phone numbers. This message is digitally signed. If your Microsoft MUA reports problems, please read http://tinyurl.com/broken-mua --tjCHc7DPkfUGtrlw Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlDPqYYACgkQIubykFB6QiMTdgCgnSbwTAVdmMhQmevW58pQkzfa 6YEAmwSLbiObOc/9ezYwrh6RS+yE9Hsh =f3VJ -----END PGP SIGNATURE----- --tjCHc7DPkfUGtrlw--
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