Date: Sun, 2 Oct 2005 16:57:09 +0200 From: Patrick Proniewski <patpro@patpro.net> To: freebsd-performance@freebsd.org Subject: dd(1) performance when copiing a disk to another Message-ID: <7035DA0C-E43C-478B-9B1C-6A32545E5E63@patpro.net>
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Hi, (carte m=E8re supermicro chip SATA Intel 6300ESB) I run FreeBSD 5.4 on a PIV 3GHz (SuperMicro motherboard, Intel SATA =20 6300ESB chipset) with 2 SATA HDD. I'm in the process to duplicate the =20= boot HDD to the second HDD. I run dd for that: # dd if=3D/dev/ad4 of=3D/dev/ad6 bs=3D1m It yields to poor performances: $ iostat -dhKw 1 (...) ad4 ad6 KB/t tps MB/s KB/t tps MB/s 124.49 252 30.69 128.00 246 30.69 128.00 285 35.64 128.00 279 34.90 128.00 282 35.27 128.00 283 35.40 (...) Is it normal that data rate won't go upper than 35/38 MB/s ? HDDs are: ad4 -> Maxtor 80 Go 7200 rpm ad6 -> Hitachi 80 Go 7200 rpm one more question: is dd(1) a good way to duplicate a boot drive to =20 make a bootable spare disk ? patpro=
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