Date: Fri, 17 Jan 2014 13:22:38 -0800 From: paul beard <paulbeard@gmail.com> To: Kevin Oberman <rkoberman@gmail.com> Cc: FreeBSD Ports <ports@freebsd.org>, bart@tapolsky.net.ua Subject: Re: clonehdd followup Message-ID: <CAMtcK2pM_Y8_gx0myVHV6PLrxi9Ac%2BWw54xz7ALz0LSet1CFiQ@mail.gmail.com> In-Reply-To: <CAN6yY1v3yjeizU7jKobE=twq4-YWko92uw2iCnKprE3Ts6gxJg@mail.gmail.com> References: <CAMtcK2rJOQz1dh9wjU5xKvTkPv%2B-U_cgzmyfbtYPF%2BpimBpKdg@mail.gmail.com> <CAMtcK2rdKdnHT1Lai8u5g5FnSZmvhBdPq_6iR_J8pjBsSJgqDQ@mail.gmail.com> <CAN6yY1v3yjeizU7jKobE=twq4-YWko92uw2iCnKprE3Ts6gxJg@mail.gmail.com>
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On Fri, Jan 17, 2014 at 1:17 PM, Kevin Oberman <rkoberman@gmail.com> wrote: > Remember that 1.5GB/s is the speed supported by the electronics and the > cache. It is not the speed that the disk actually reads or writes from/to > the platters. When cloning, very little of the data is in cache, so you are > generally limited by seek times (should be minimal if the code is well > done) and rotational speed. The really then boils down to transfer speeds > are going ot be close to what is possible with the rotational speed. > Yeah, I knew 1.5G was our old friend, the theoretical maximum, or his cousin, the optimal transfer rate. I was hoping for something better than 500M/minute. I'm sure there are any number of factors that are slowing things down. It seemed like incorporating the larger blocks/boundary alignment might help. I'm testing it now and I'm not sure I'm seeing it. -- Paul Beard / www.paulbeard.org/
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