Date: Thu, 3 Sep 2009 00:11:38 +1000 From: Emil Mikulic <emikulic@gmail.com> To: "Derek (freebsd lists)" <482254ac@razorfever.net> Cc: freebsd-current@freebsd.org Subject: Re: siis/atacam/ata/gmirror 8.0-BETA3 disk performance Message-ID: <20090902141138.GA15045@dmr.ath.cx> In-Reply-To: <4A9E5F34.2090700@razorfever.net> References: <4A9E5F34.2090700@razorfever.net>
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On Wed, Sep 02, 2009 at 08:04:04AM -0400, Derek (freebsd lists) wrote: > Hi, > > I've been testing the new siis driver, and I have found no > appreciable performance change, using dd as a measure of "raw" > performance. > > I get about 40MB/s read, and 30MB/s write. See attached > bench-*.txt files. [...] > ada0: <ST31500341AS CC1H> ATA/ATAPI-8 SATA 2.x device > ada0: 1430799MB (2930277168 512 byte sectors: 16H 63S/T 16383C) Huh, I have the same disk: # dmesg | grep ad4 ad4: 1430799MB <Seagate ST31500341AS CC1H> at ata2-master SATA300 Sequential read on a disk this size should be around 120MB/sec at the outer tracks: # dd if=/dev/ad4 of=/dev/null bs=128k count=5000 655360000 bytes transferred in 5.171389 secs (126728039 bytes/sec) > Also I find it surprising that my gmirror read is only 40MB/s, > and not 60-80MB/s, any thoughts on this? Stripe will give you higher throughput. Mirror will give you more random seeks per second. --Emil
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