Date: Wed, 01 Mar 2006 12:03:42 +0000 From: Alex Zbyslaw <xfb52@dial.pipex.com> To: Beastie <beastie@mra.co.id> Cc: Liste FreeBSD <freebsd-questions@freebsd.org> Subject: Re: SATA Raid (stress test..) Message-ID: <44058D9E.3010801@dial.pipex.com> In-Reply-To: <440565FF.3030002@mra.co.id> References: <61560.207.70.139.52.1139628926.squirrel@www.compedgeracing.com> <6C543300-579C-4313-A355-0F26181B3FA7@todoo.biz> <067101c63216$a7682f10$c801a8c0@nexpc> <65260.207.70.139.52.1139998857.squirrel@www.compedgeracing.com> <06b901c63220$3a849eb0$c801a8c0@nexpc> <50778.207.70.139.52.1140002253.squirrel@www.compedgeracing.com> <43F3EDD6.80707@mra.co.id> <44052663.7000802@mra.co.id> <440565FF.3030002@mra.co.id>
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Beastie wrote: > I try to test with dd simple command > > dd if=/dev/amrd0s1d of=/dev/null > ^C31297+0 records in > 31297+0 records out > 16024064 bytes transferred in 7.970548 secs (2010409 bytes/sec) > > the result is very slow performance (-+ 2 Mbytes/sec), with write > cache enable on drive. :( Your performance sucks because, to quote the manual, "Input data is read and written in 512-byte blocks". Try a sensible blocksize. 16k would mimic a standard file system block, but even that is likely to underestimate. If you were, say, copying the disk to another you could easily use 1Mb. Some examples: dd if=/dev/ad10s1a of=/dev/null ^C794830+0 records in 794830+0 records out 406952960 bytes transferred in 164.049297 secs (2480675 bytes/sec) dd if=/dev/ad10s1a of=/dev/null bs=16k ^C53745+0 records in 53745+0 records out 880558080 bytes transferred in 21.092098 secs (41748245 bytes/sec) So from 2Mb/s to 41Mb/s! dd if=/dev/ad10s1a of=/dev/null bs=1m ^C933+0 records in 933+0 records out 978321408 bytes transferred in 13.836165 secs (70707556 bytes/sec) And up to 70Mb/s though nothing real world is likely to achieve that. There are a whole slew of ports (/usr/ports/benchmarks) some of which do disk tests. I've used unixbench in the past, which is a bit of a faff and does more than disks, but it works. If you run windows on the box and want graphical benchtests, then there are free apps out there that will do tests on disks, like Sandra. --Alex
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