Cisco MDS 9000 Series Configuration Manual page 159

Congestion Detection, Avoidance, and Isolation
fc1/1
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fc1/1
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fc1/1
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fc1/1
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fc1/1
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fc1/1
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fc1/1
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The following example displays instances of credit loss recovery (transmitted LCR) initiated by a link
failure:
switch# show logging log | i i timeout
...
2018 Aug 17 12:54:59 MDS9710 %PORT-5-IF_DOWN_LINK_FAILURE: %$VSAN 1%$ Interface fc1/2
is down (Link failure Link reset failed due to timeout) port-channel228
2018 Aug 17 13:42:01 MDS9710 %PORT-5-IF_DOWN_LINK_FAILURE: %$VSAN 1%$ Interface fc1/2
is down (Link failure Link reset failed due to timeout)
The following example displays LRR received on a port:
switch# show interface fc1/1 counters details
fc1/1
...
initiated from the adjacent device
...
The following example displays LCR received failing due to severe ingress congestion:
switch# show log last 20
2018 Aug 22 09:58:17 MDS9710 %ETHPORT-5-IF_BANDWIDTH_CHANGE: Interface
ethernet-port-channel650,bandwidth changed to ...
2018 Aug 22 10:21:44 MDS9710 %PORT-5-IF_DOWN_LINK_FAILURE: %$VSAN 237%$ Interface fc1/13
is down (Link failure Link Reset failed nonempty recv queue)
• Level 2
Level 2 slow-drain condition indicates that the links are so congested that the received frames that are
destined for the congested links cannot be transmitted within the congestion-drop threshold. When this
condition occurs, these frames are discarded or dropped as timeout-drops. These dropped frames cause
SCSI exchanges to fail at the end hosts. Timeout discards are mostly accompanied by level 1 or level
1.5 congestion.
Timeout-drops are displayed in the following ways:
|F16_TMM_TOLB_TIMEOUT_DROP_CNT
|FCP_SW_CNTR_TX_WT_AVG_B2B_ZERO
|FCP_SW_CNTR_CREDIT_LOSS
|F16_TMM_TOLB_TIMEOUT_DROP_CNT
|FCP_SW_CNTR_TX_WT_AVG_B2B_ZERO
|F16_TMM_TOLB_TIMEOUT_DROP_CNT
|FCP_SW_CNTR_TX_WT_AVG_B2B_ZERO
27651428465 frames, 59174056872960 bytes received
0 link reset received while link is active
18 link reset responses received
0 link reset responses transmitted
Cisco MDS 9000 Series Interfaces Configuration Guide, Release 8.x
Information About Congestion Detection
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|1781544
|10
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|11881213
|1781307
<<<<< Credit loss recovery
<<<<< LRRs received
<<<<< LRRs transmitted
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