Date: Mon, 09 May 2005 21:56:05 -0400 From: Mike Tancsa <mike@sentex.net> To: Dan Nelson <dnelson@allantgroup.com> Cc: freebsd-hackers@freebsd.org Subject: Re: Low HDD tranfer rate with FreeBSD 5.3-Release Message-ID: <0350819dcs9asmaioaqo4kuhhsqmlg0t06@4ax.com> In-Reply-To: <20050509190245.GF38839@dan.emsphone.com> References: <427FA802.90805@chamkila.org> <427FA8CD.8040405@centtech.com> <427FAB5F.6070508@chamkila.org> <427FAF73.7070702@centtech.com> <20050509190245.GF38839@dan.emsphone.com>
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On Mon, 9 May 2005 14:02:45 -0500, in sentex.lists.freebsd.hackers you
wrote:
>
>Yes, try 64k instead of 8k, and also compare read speeds. If you have
>the time (could take an hour or so), try "dd if=3D/dev/ad0 =
of=3D/dev/null
>bs=3D64k", run an "iostat 60" in another window, let the dd run through
>the entire disk, and compare the relative speeds from start to finish.
>
>For the DiamondMax 160, the sustained throughput should be 26MB -> 50MB
>as you go from inner to outer tracks.
Not sure how honest diskinfo is, but the numbers do seem somewhat
reasonable for checking these values.
[releng5-865]# diskinfo -t ad0
ad0
512 # sectorsize
40020664320 # mediasize in bytes (37G)
78165360 # mediasize in sectors
77545 # Cylinders according to firmware.
16 # Heads according to firmware.
63 # Sectors according to firmware.
Seek times:
Full stroke: 250 iter in 5.641185 sec =3D 22.565 msec
Half stroke: 250 iter in 4.381489 sec =3D 17.526 msec
Quarter stroke: 500 iter in 7.043785 sec =3D 14.088 msec
Short forward: 400 iter in 1.625114 sec =3D 4.063 msec
Short backward: 400 iter in 1.524874 sec =3D 3.812 msec
Seq outer: 2048 iter in 0.233424 sec =3D 0.114 msec
Seq inner: 2048 iter in 0.224814 sec =3D 0.110 msec
Transfer rates:
outside: 102400 kbytes in 1.787498 sec =3D 57287
kbytes/sec
middle: 102400 kbytes in 2.175933 sec =3D 47060
kbytes/sec
inside: 102400 kbytes in 3.416033 sec =3D 29976
kbytes/sec
[releng5-865]#=20
---Mike
--------------------------------------------------------
Mike Tancsa, Sentex communications http://www.sentex.net
Providing Internet Access since 1994
mike@sentex.net, (http://www.tancsa.com)
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