[PLUG] SATA2 not faster - was Re: Fixed T60 slow ...

Daniel Pittman daniel at rimspace.net
Tue Jan 11 00:47:09 UTC 2011


On Mon, Jan 10, 2011 at 15:21, Keith Lofstrom <keithl at kl-ic.com> wrote:
> On Mon, Jan 10, 2011 at 10:18:58AM -0800, Keith Lofstrom wrote:

>> I expect the SATAII connection will be quite a bit faster,
>> since I will be using different buses to stream the data
>> from drive to drive.
>
> Uh ... no.  The SATAII stuff arrived.  While hdparm -t for the
> SATA2 interface says 90.7 MB/s, the dd command runs at 50.7 MB/s
> with the SATA2 hardware, as opposed to 47.7 MB/s with the Ultrabay
> and translator.   So my expectation was false.  Or perhaps there
> is a faster way to run "dd" than merely setting the blocksize to
> 8M (handling the data in larger chunks tends to save time).

Nah, not really – it sounds like you have found the sustained transfer
rate of the drive, rather than the burst transfer rate.  (The link
rate in SATA 1 was enough for anything production until SSD made a big
showing, and SATA 2 is still has some headroom compared to the
non-enterprise stuff.)

Regards,
    Daniel
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✉ Daniel Pittman <daniel at rimspace.net>
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