Re: [gentoo-user] {OT} USB 3.0 hard drive speed test

[Simon <turner25@gmail.com>]

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It is my opinion that benchmarks should be done with a real benchmark tool.

Try with bonnie++
This will really show you the strengths and weaknesses of your setup.

Good luck,
  Simon

On Thu, Aug 11, 2011 at 1:49 PM, Volker Armin Hemmann <
volkerarmin@googlemail.com> wrote:

> Am Donnerstag 11 August 2011, 10:30:04 schrieb Mark Knecht:
> > On Thu, Aug 11, 2011 at 10:12 AM, Grant <emailgrant@gmail.com> wrote:
> > > I'm testing this USB 3.0 bus-powered hard drive:
> > >
> > > http://www.amazon.com/gp/product/B0041OSQ9S
> > >
> > > and I get:
> > >
> > > # hdparm -tT /dev/sdb
> > > /dev/sdb:
> > > Timing cached reads:   8006 MB in  2.00 seconds = 4004.33 MB/sec
> > > Timing buffered disk reads: 252 MB in  3.01 seconds =  83.63 MB/sec
> > >
> > > # hdparm -tT /dev/sdb
> > > /dev/sdb:
> > > Timing cached reads:   8230 MB in  2.00 seconds = 4116.54 MB/sec
> > > Timing buffered disk reads: 252 MB in  3.02 seconds =  83.55 MB/sec
> > >
> > > # hdparm -tT /dev/sdb
> > > /dev/sdb:
> > > Timing cached reads:   8446 MB in  2.00 seconds = 4224.36 MB/sec
> > > Timing buffered disk reads: 230 MB in  3.02 seconds =  76.28 MB/sec
> > >
> > > Wikipedia says USB 3.0 has transmission speeds of up to 5 Gbit/s.
> > > Doesn't MB/sec denote mega*bytes* per second?
> > >
> > > - Grant
> >
> > 4000MB/s = 4Gb/s
>
>
> please read man hdparm
>
>  -T     Perform timings of cache reads for benchmark and comparison
> purposes.
> For meaningful results,  this  operation
>              should be repeated 2-3 times on an otherwise inactive system
> (no
> other active processes) with at least a couple
>              of megabytes of free memory.  This displays the speed of
> reading
> directly from the Linux buffer  cache  without
>              disk access.  This measurement is essentially an indication of
> the throughput of the processor, cache, and mem-
>              ory of the system under test.
>
>
> as you can see, those numbers have nothing to do with the transport.
>
> And 80mb/sec for a harddisk is really, really good.
>
> --
> #163933
>
>

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