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Re: [Xen-users] Shared Storage



On Apr 26, 2011, at 6:37 PM, Eduardo Bragatto wrote:

On 04/26/2011 04:31 PM, Javier Guerra Giraldez wrote:
Some good summary numbers are near the bottom here (PDF):

http://www.google.com/url?sa=t&source=web&cd=1&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.rainiersolutions.com%2FRainierLibrary%2FiSCSI%2520SAN%2520Performance.pdf&rct=j&q=iscsi%20throughput%20gigabit&ei=NC63TaGhI8n50gGJl4kF&usg=AFQjCNGqiaj31yc3XYue97OL9KpPyo_zDg&cad=rja

With a MTU of 1500, they're claiming 94.93% payload. On GbE, I don't believe I've seen more than ~100MB/s on any protocol, hence my estimate of 20% overhead.

John

In sequential writes I get nearly all the 125MB/s using iSCSI on BCM5709 without the iSCSI Offload module enabled (better yet, module is loaded but reporting my cards do not support it, although they do).

It fluctuates from normally 120MB/s to rarely 125MB/s.


Oooops, my bad. I decided to double check after I posted and after doing a 10GB sequential write, I realized the software I used to test was using 10^9 for GB instead of 1024^3, resulting in higher rates than in reality.

After redoing the math using the correct amount of data transfered, I got to 113MB/s which is what the document defines as the maximum theoretical throughput.

Best regards,
Eduardo

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