Re: Equallogic PS4110X Flow Control problem

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FYI:  That message will only appear if the array is running 6.0.x firmware and DCB is enabled and negotiated.  Not all 10GbE switches support the specific features iSCSI needs for DCB.   The 8024 is one of the switches that does not yet include the needed features.  You should open a support case to insure that DCB is properly disabled on that switch.

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kfaz
1 Copper

Re: Equallogic PS4110X Flow Control problem

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So how could you explain this message:

806:311:EQL6110-1:SP:23-Nov-2012 15:54:12.021766:emm.c:2501:INFO:28.2.131:Ethernet flow control is now enabled on all interfaces.

BTW: I have the newest image (5.0.1.3) installed on the switch.

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kfaz
1 Copper

Re: Equallogic PS4110X Flow Control problem

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I've double checked it and it seems to be totally non deterministic. My solution works for one eql storage and doesn't work for another. Both arrays have same firmware revision and are connected to same stacked switches with identically configured ports and only one reports problem.

So probably I'll have to disable DCB which is not the best solution 😕

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Re: Equallogic PS4110X Flow Control problem

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What the original message is saying is:  "Since I couldn't negotiate the Prioritized Flow Control (PFC) part of DCB,  I can't use it, since DCB is enabled I also can't use 'traditional' link level flowcontrol as a fall back"  

When you changed the LLDP setting that seems to have turned off DCB, which allowed LL Flowcontrol to be negotiated.  Disabling LLDP is one way to disable DCB.

Suggest you open a case with the Power Connect team on the best way to turn off DCB.    The 8100 series fully supports DCB I'm not sure if a future FW release will also do that for the 8000 series switches.

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rasheedmgs
1 Copper

Re: Equallogic PS4110X Flow Control problem

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Thank you so much!!! This helped me a lot. I am seeing the warning many days ago.

Please tell me if i upgrade the eql firmware then, is there any performance issue with I/O reads & writes?

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Re: Equallogic PS4110X Flow Control problem

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Earlier in this thread, I said to disable DCB in the EQL GUI.  That's not correct.  DCB should only be disabled on the physical switches.

Re: Upgrade I'm not sure what you are asking.  Are you asking about performance impact during the FW upgrade process?

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Re: Equallogic PS4110X Flow Control problem

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Also specifically on the Dell Power Connect 8024 series you have to first upgrade to the current 5.x firmware to disable DCB.

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balazslevai
1 Copper

RE: Equallogic PS4110X Flow Control problem

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Hi Dell-Donald Wi,

I have been tasked with turning off dcb on a port of a Dell 8024k switch. Could you give me a step-by step guide on how to do it via CLI?

Thank you!

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RE: Equallogic PS4110X Flow Control problem

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Hello, 

 You will need to make sure you are at current switch firmware, then you can disable DCB globally, not per port. 

This guide shows how to do it. 

http://en.community.dell.com/techcenter/extras/m/white_papers/20437136

This link has info on best practices with DCB and includes some text on configuration.  

http://en.community.dell.com/dell-groups/dtcmedia/m/mediagallery/20305369/download

Regards,

Don 

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dell-richard g
3 Silver

RE: Equallogic PS4110X Flow Control problem

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Additional info that may help:

1.  DCB will automatically be disabled if you disable LLDP.  This is because DCB parameters are communicated via LLDP packets.  So if you turn off LLDP, it will turn off DCB as well.  Since many environments use LLDP, turning off LLDP is not an option.

2.  Edge devices like NICs and storage devices are in "willing mode", meaning they always inherit DCB parameters from a source switch.  So if you want to completely disable DCB in your network, you turn it off on the switch.   Some edge devices allow you to disable DCB, usually via the option ROM.

3.  It's not good practice to disable DCB on one edge device (i.e. EQL) and leave it enabled at the other end point (i.e. server NIC).  This causes flow control incompatibilities.

4.  On the PC8024, you can try to disable DCB on the interface itself via the following commands:

no lldp tlv-select dcbxp ets-config

no lldp tlv-select dcbxp ets-recommend

no lldp tlv-select dcbxp pfc

no lldp tlv-select dcbxp application-priority

Also, be sure to disable DCB globally via the "no dcb enable" command.

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