[Stgt-devel] A curious observation with iSCSI and SCSI tgt ...

Richard Sharpe realrichardsharpe
Fri Jul 25 20:46:14 CEST 2008

On Wed, Jul 2, 2008 at 2:01 PM, Richard Sharpe
<realrichardsharpe at gmail.com> wrote:
> Hi,
> I am testing some configurations I have laying around here at work while
> waiting for our new hardware to arrive.
> I set up one system, a 1U with 2GB of memory and a Xeon (speed not really
> relevant to this) and GigE as a target and set up a virtual disk via iSCSI.
> Then on another system, an old DELL, I set up the initiator, and ran:
>    dd if=/dev/zero of=/dev/sda1 bs=1024 count=1000000
> and I got a throughput of 10.5-10.8MB/a while consuming around 10-12% of the
> CPU on the target (shown via top).

OK, I have shifted to faster machines (a couple of 1U Tyan B5211s with
Quad core Xeon X3230  @ 2.66GHz and jumbo frames ...)

I get around 58.6MB/s with 819MB but it drops to 44-45MB/s with 8GB
files (with a variety of block sizes (4096, 8192, 16384).

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