Date: Tue, 19 Oct 2004 14:46:32 -0400 (EDT) From: "Mike Jakubik" <mikej@rogers.com> To: "Kenneth Culver" <culverk@sweetdreamsracing.biz> Cc: freebsd-current@freebsd.org Subject: Re: FreeBSD 5.3b7and poor ata performance Message-ID: <4129.192.168.0.188.1098211592.squirrel@192.168.0.188> In-Reply-To: <20041019104525.ikgw8kcw8sw480os@www.sweetdreamsracing.biz> References: <20041015190638.C5A0E5D04@ptavv.es.net> <41715E7F.7060509@ng.fadesa.es> <20041018100045.f8koww0skcco0woo@www.sweetdreamsracing.biz> <4173D66F.6010200@DeepCore.dk> <4173F2E9.7010407@ng.fadesa.es> <417406E3.9010706@DeepCore.dk> <4174FD04.8040000@ng.fadesa.es> <20041019104525.ikgw8kcw8sw480os@www.sweetdreamsracing.biz>
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Kenneth Culver said: > Quoting fandino <fandino@ng.fadesa.es>: > >> Søren Schmidt wrote: >>>> # dd if=/dev/ad4 of=/dev/null bs=1024k count=1024 >>>> 1024+0 records in >>>> 1024+0 records out >>>> 1073741824 bytes transferred in 31.090536 secs (34535970 bytes/sec) >>> >>> etc, and I get this: >>> 1073741824 bytes transferred in 18.488903 secs (58074934 bytes/sec) >>> 1073741824 bytes transferred in 14.956484 secs (71791059 bytes/sec) >> > ad4: 114440MB <Maxtor 6Y120M0/YAR51EW0> [232514/16/63] at ata2-master > SATA150 > ad6: 114440MB <Maxtor 6Y120M0/YAR51EW0> [232514/16/63] at ata3-master > SATA150 > > Set up for striping: > > ar0: 228880MB <ATA RAID0 array> [29178/255/63] status: READY subdisks: > disk0 READY on ad4 at ata2-master > disk1 READY on ad6 at ata3-master > > I get the following performance with dd: > > dd if=/dev/ad4 of=/dev/null bs=1m count=200 > 200+0 records in > 200+0 records out > 209715200 bytes transferred in 3.538456 secs (59267433 bytes/sec) > > dd if=/dev/ad6 of=/dev/null bs=1m count=200 > 200+0 records in > 200+0 records out > 209715200 bytes transferred in 3.551439 secs (59050767 bytes/sec) > > dd if=/dev/ar0 of=/dev/null bs=1m count=200 > 200+0 records in > 200+0 records out > 209715200 bytes transferred in 1.837508 secs (114130226 bytes/sec) > > This is with a custom kernel with all debugging options off. I haven't > seen a > mail from you yet that says whether you turned off debugging options in > the > kernel or not, and if you haven't turned off debugging options, I'd > strongly > suggest doing so. Out of curiosity, i ran this on one of our production servers, which runs on a dual Xeon MB, with SCSI raid-10 setup, and to my surprise here are the results: CPU: Intel(R) Xeon(TM) CPU 2.80GHz (2799.22-MHz 686-class CPU) real memory = 2146959360 (2047 MB) avail memory = 2099650560 (2002 MB) FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs da0 at asr0 bus 0 target 0 lun 0 da0: <ADAPTEC RAID-10 3B0A> Fixed Direct Access SCSI-2 device FreeBSD 5.3-BETA4 #0: Sun Sep 12 13:09:43 EDT 2004 (Custom kernel, no debugging) # dd if=/dev/da0 of=/dev/null bs=1m count=200 200+0 records in 200+0 records out 209715200 bytes transferred in 6.225309 secs (33687517 bytes/sec) Why is a SCSI raid-10 system slower than a plain IDE disk? Something is wrong here.
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