Re: [PLUG] Disk Transfer Speeds

[Casey Bralla <MailList@NerdWorld.org>]

You're right.  I was confusing Bytes with Bits.  KDE reports the speed as MB/s, which I 
had assumed was bits.   A quick calculation confirmed it is bytes.

Now it makes sense.   Thanks!

On Monday 24 March 2008 12:58:29 pm Brian Stempin wrote:
> Oh, one other thing:
>
> Are you being careful between M*Bits* and M*Bytes*?  There's a pretty large
> difference.  A 100Mbit/sec connection = 12.5 MBytes/sec (remember:  there
> are 8 bits per byte).  Once you count in TCP/IP overhead (usually between
> 15% and 25%, depending on who you ask, jumbo frame settinsg, etc),
> 9MBytes/sec is a fair throughput.  I want to say that the fastest I've ever
> gotten on a 100Mbit connection was around 10.2MBytes/sec.
>
> Anyways, all of that text to say, "Even if you had faster hard drives, your
> network throughput wouldn't go up that much anyway, if at all."
>
> On Mon, Mar 24, 2008 at 12:42 PM, Brian Vagnoni <bvagnoni@v-system.net>
>
> wrote:
> > From what I've read network speed auto negotiation is a real throughput
> > killer. Interfaces should be manually set to 100mB full duplex if the
> > card and switch can handle it. Also check for accessive broadcast traffic
> > another throughput killer.
> >
> > Brian Vagnoni
> > PGP Digital Fingerprint
> >
> > F076 6EEE 06E5 BEEF EBBD BD36 F29E 850D FC32 3955
> >
> > -----Original Message-----
> > From: Casey Bralla <MailList@NerdWorld.org>
> > Sent: Saturday, March 22, 2008 7:15 AM
> > To: Philadelphia Linux User's Group Discussion List <
> > plug@lists.phillylinux.org>
> > Subject: [PLUG] Disk Transfer Speeds
> >
> > How fast are file transfers on your computer?
> >
> > Recently, I noticed that some of my networked servers seemed very slow.
> >  On large (100+
> > MByte) file transfers, I was getting rates less than 1 MBit/sec. 
> > Changing out an old
> > 10 MBit/sec hub to a 100 MBit/sec switch increased the speed to about 8-9
> > MBits/sec.
> > A little more investigation revealed that *local* transfers (on the same
> > disk) maxed
> > out at about 9 MBits/sec.  This seems to point to a limitation on the
> > disk itself.
> >
> > This still seems slow to me.
> >
> > I've got a fairly good computer:  AMD 3400+, 2 GBytes of RAM, Gentoo,
> > KDE, ReiserFS,
> > Disk DMA active, with a half-dozen programs running.
> >
> >
> > I'm curious what speeds other people get with large files.  (Gotta be
> > sure that the
> > file is bigger than the cache to keep from getting bogus numbers)
> >
> > --
> >
> >
> > Casey Bralla
> > Chief Nerd in Residence
> > The NerdWorld Organisation
> >
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-- 


Casey Bralla
Chief Nerd in Residence
The NerdWorld Organisation
___________________________________________________________________________
Philadelphia Linux Users Group         --        http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
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