Date: Fri, 2 Mar 2007 02:35:56 -0800 (PST) From: "R. B. Riddick" <arne_woerner@yahoo.com> To: "O. Hartmann" <ohartman@zedat.fu-berlin.de>, freebsd-performance@freebsd.org, freebsd-questions@freebsd.org Subject: Re: (S)ATA performance in FBSD 6.2/7.0 Message-ID: <455296.79993.qm@web30315.mail.mud.yahoo.com> In-Reply-To: <45E7F09B.7070005@zedat.fu-berlin.de>
next in thread | previous in thread | raw e-mail | index | archive | help
--- "O. Hartmann" <ohartman@zedat.fu-berlin.de> wrote: > Before digging into this problem deeper with benchmarks, could anyone > explain why FreeBSD reaches this 33 MB/s limit (sounds like UDMA 33 > defaults, but on both boxes nForce4 and ICH5 controller are recognized > and show up with SATA300 or SATA150 capabilities, respective)? May I > have some knobs I'm not aware of to tune disk performance? > I think, this 33MB/sec limit comes like this: The regular copy process (I think u used "cp") reads with speed S from disk A and writes with speed S to disk B. But: While it reads, it doesnt write AND while it writes, it doesnt read. So you might want to try this: dd if=/diskA/fileA bs=128k | dd of=/diskB/fileB bs=128k You could also try just to read or to write. Or to read&write with _independent_ processes. -Arne ____________________________________________________________________________________ The fish are biting. Get more visitors on your site using Yahoo! Search Marketing. http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?455296.79993.qm>