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<TITLE>RE: [openib-general] IB and FC</TITLE>
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<P><FONT SIZE=2>> From: Mohit Katiyar, Noida [<A HREF="mailto:mohitka@noida.hcltech.com">mailto:mohitka@noida.hcltech.com</A>]</FONT>
<BR><FONT SIZE=2>> Sent: Saturday, October 15, 2005 3:40 PM</FONT>
</P>
<P><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> While in the figure given below the client to IB FC gateway speed is ></FONT>
<BR><FONT SIZE=2>> 10 GB/s and from Gateway to I/O storage is 2GB/s and if port </FONT>
<BR><FONT SIZE=2>> aggregation</FONT>
<BR><FONT SIZE=2>> is applied at gateway then 4GB/s. So the total effective speed from</FONT>
<BR><FONT SIZE=2>> client to I/O storage can max be reached at 4GB/s</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> IB cables </FONT>
<BR><FONT SIZE=2>> Client ----|</FONT>
<BR><FONT SIZE=2>> Client -- -| |----- FC Switch---|</FONT>
<BR><FONT SIZE=2>> . | IB cables | |</FONT>
<BR><FONT SIZE=2>> . |--IB FC ------ | |-------I/O storage</FONT>
<BR><FONT SIZE=2>> | Gateway | |</FONT>
<BR><FONT SIZE=2>> Client ----| Router |----- FC Switch---|</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Figure 2</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> So can anyone explain me am I correct in my approach? Are there any</FONT>
<BR><FONT SIZE=2>> other advantages in shifting from figure 1 architecture to figure 2</FONT>
<BR><FONT SIZE=2>> architecture?</FONT>
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<P><FONT SIZE=2>The Gateway from IB to FC can also be a storage virtualization device, in which</FONT>
<BR><FONT SIZE=2>case it may stripe data amongst multiple FC devices. In this case you can get higher</FONT>
<BR><FONT SIZE=2>bandwidth (aggregate) to the storage boxes, because there are going to be many of them. Caching may also be doable in the gateway.</FONT></P>
<P><FONT SIZE=2>This may also be an intermediate solution that will enable you to connect native</FONT>
<BR><FONT SIZE=2>IB storage boxes in the future. In which case you're going to be able to </FONT>
<BR><FONT SIZE=2>connect both your existing FC storage boxes and new IB storage boxes to the IB fabric.</FONT>
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<P><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> It does not seem any advantageous in shifting from FC SAN to IB FC SAN</FONT>
<BR><FONT SIZE=2>> through such a pattern?</FONT>
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<P><FONT SIZE=2>Another reason can be cost. If your clients already have IB adapters because they</FONT>
<BR><FONT SIZE=2>are doing clustering or for other reason, then why buy a FC adapter to each client ?</FONT>
<BR><FONT SIZE=2>Just use the IB as a consolidated fabric and through the GW you can access the storage. You saved the cost of the FC adapters.</FONT></P>
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