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Fibre Channel (SAN)

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Occasional Contributor
Posts: 12
Registered: ‎05-08-2019

Re: Poor performance and latency issues

Here's an output for the Rx Tx power.

SFPRxPowerdBm SFPRxPoweruW SFPTxPowerdBm SFPTxPoweruW
-3.2 483.8 -3.3 467.9
-3.2 483.8 -3.3 467.9
-3.2 483.8 -3.3 467.9
-3.2 483.8 -3.3 467.9
-3.2 483.8 -3.3 467.9
-3.2 483.8 -3.3 467.9
-3.2 483.8 -3.3 467.9
-4.4 362.5 -2.7 537.8
-4.4 362.5 -2.7 537.8
-3.4 454.8 -3 506.7
-3.4 454.8 -3 506.7
-3.8 414 -2.4 582.1
-3.8 414 -2.4 582.1
-3.8 414 -2.4 582.1
-3.8 414 -2.4 582.1
-3.8 414 -2.4 582.1
-3.8 414 -2.4 582.1
-3.8 414 -2.4 582.1
-3.8 414 -2.4 582.1
-2.4 578.3 -2.4 574.1
-2.4 578.3 -2.4 574.1
-2.7 541.7 -2.6 543.4
-2.7 541.7 -2.6 543.4
-2.7 541.7 -2.6 543.4
-1.9 651.2 -2.5 559.1
-1.9 651.2 -2.5 559.1
-1.9 651.2 -2.5 559.1
-3.9 403.5 -2.4 577.6
-3.5 451.8 -2.4 574.8
-2.4 575.6 -3.4 453.1
-2.6 550.3 -2.6 547.2
-3.7 429.8 -3.5 447.1
-3.2 478.1 -2.5 563.1
-1.5 709 0.2 1057.6
-2.2 606.4 -3.2 483
-2.1 610.4 -3.3 471.7
-2.1 622.9 -2.4 578.9
-2.5 563.3 -2.4 573.4
-2.6 550.8 -2.6 555
-3.1 486.8 -2.5 562.8
-11.5 70.8 -2.5 567.9
-11.5 70.8 -2.5 567.9
-13.4 45.5 -2.4 574.2
-13.4 45.5 -2.4 574.2
-11.1 78.3 -2.3 592.7
-11.1 78.3 -2.3 592.7
-11.3 73.7 -3 503.5
-11.3 73.7 -3 503.5
-10.2 95.3 -2.6 550
-10.2 95.3 -2.6 550
-9.3 118.2 -2.6 551.1
-9.3 118.2 -2.6 551.1
-3 497.7 -2.3 591.7
-3 497.7 -2.3 591.7
-2.8 522.8 -2.4 577.2
-2.8 522.8 -2.4 577.2
-3.6 432.1 -2.3 587.7
-3 497.9 -2.3 594.5
-3.1 494 -2.7 542.8
-3.6 435.8 -2.3 585.7
-2.9 514.6 -2.2 607.7
-2.9 514.6 -2.2 607.7
-2 631.3 -2.4 573.3
-2 631.3 -2.4 573.3
-2.2 607.6 -2.2 603.7
-2.2 607.6 -2.2 603.7
-2 625 -2.3 592.3
-2 625 -2.3 592.3
-2.6 543.6 -2.2 607.1
-2.6 543.6 -2.2 607.1
-2.6 544.8 -2.3 588.4
-2.6 544.8 -2.3 588.4
-2.8 528.2 -2.2 600.9
-2.8 528.2 -2.2 600.9
-2.6 553.1 -2.2 600.6
-2.6 553.1 -2.2 600.6
-3.4 458.4 -2.2 605.8
Regular Contributor
Posts: 171
Registered: ‎03-20-2018

Re: Poor performance and latency issues

This grouping is rather low. Is this RX or TX? (I would assume RX...)

 

-11.5 70.8 -2.5 567.9
-11.5 70.8 -2.5 567.9
-13.4 45.5 -2.4 574.2
-13.4 45.5 -2.4 574.2
-11.1 78.3 -2.3 592.7
-11.1 78.3 -2.3 592.7
-11.3 73.7 -3 503.5
-11.3 73.7 -3 503.5
-10.2 95.3 -2.6 550
-10.2 95.3 -2.6 550
-9.3 118.2 -2.6 551.1
-9.3 118.2 -2.6 551.1

 

I would recommend reviewing all the cabling.

Regular Contributor
Posts: 171
Registered: ‎03-20-2018

Re: Poor performance and latency issues

If you want to see the ports associated with this, run:

 

sfpshow -all | grep -e Port -e Power

 

The grep portion is case sensitive.

Regular Contributor
Posts: 171
Registered: ‎03-20-2018

Re: Poor performance and latency issues

Yes, All are set to AutoNegotiate, and I've found that one of the ISLs detects the speed as 8G, despite the fact that the SFP is 16G. I will set the speed to manual.

 

I would recommend not setting the speed to manual as it might cause other issues. Instead, it does look as though we have something specific to look at. IE: That port/cable set.

Occasional Contributor
Posts: 12
Registered: ‎05-08-2019

Re: Poor performance and latency issues

I will review the cables, and I won't set the speed to manual as recommended.

Thanks,
Highlighted
Regular Contributor
Posts: 171
Registered: ‎03-20-2018

Re: Poor performance and latency issues

With a port to focus on, there are quite a few commands that could shed some light (pun) on the issue.

 

errdump (with a text capture)

porterrshow

portlogshow

portlogshowport

portshow

portstatsshow

 

Other commands that might be useful:

trunkshow

fabricshow

islshow

 

These are a good starting place.

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