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If I have a switch, nothing special set up, just regular traffic, no jumbo frames, no special iSCSI set up, can I still have iSCSI traffic, say from a Windows machine using the iSCSI initiator and a SAN across that uses said switch device?

Granted I might want to use the jumbo frames, but do I need a switch that has an iSCSI "mode"?

EDIT: I have a Dell Powerconnect 6224 and it has an option for iSCSI enable. Right now I have iSCSI running on it with no jumbo frames. It's a very small set of devices.

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    There's no such thing as "iSCSI mode" on a switch that I've ever seen or heard of. – joeqwerty Feb 4 '16 at 23:24
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    OK, I see what they're doing with the iSCSI Enable setting. They're configuring specific settings that they deem to be optimal for iSCSI traffic, such as Jumbo Frames, Spanning Tree PortFast, Flow Control and Storm Control. I wouldn't call that iSCSI mode, but I see what they're doing. – joeqwerty Feb 5 '16 at 0:33
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No - iSCSI runs over IP, the switch doesn't need to know how to specifically handle it for iSCSI to run.

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  • This is partially correct. Yes iSCSI runs over TCP but switch has to have buffers deep enough and flow control being at least tested and matching iSCSI traffic. You can google for "cisco iscsi buffer" to get quite a lot of threads where people complain about flaky performance with cheap switches and iSCSI just from what I've told. supportforums.cisco.com/discussion/11285176/… <-- for example !! – BaronSamedi1958 Feb 6 '16 at 19:04
  • Well, I didn't say it'd run well, necessarily! :) – Shane Madden Feb 6 '16 at 19:06
  • LOL You right ;)) – BaronSamedi1958 Feb 7 '16 at 0:02
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Dell's iSCSI mode just tracks targets and initiators, all you should really be doing is follow the specific best practices for that switch/SAN, usually this is

MTU 9k+ (Force10 use 12k)

Flow control rx on tx off

Never do port channels, each interface should have a single ip, use multipath to aggregate links.

Avoid vlan tagging

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