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Dell Brocade G620 Brocade 8.0.1 Fabric OS Troubleshooting and Diagnostics Guid - Page 42

Troubleshooting a marginal link, Run D_Port tests.

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Connectivity The portLoopbackTest command is used to verify the functional operation of a path on a switch. This test sends frames from a given port's transmitter and loops them back into the same port's receiver. The loopback is done at the parallel loopback path. The path traversed in this test does not include the media or the fiber cable. Only one frame is transmitted and received at any given time. An external cable is not required to run this test. The port LEDs flicker green rapidly while the test is running. Table 5 shows the different loopback modes you can use when using portLoopbackTest to test a marginal link. TABLE 5 Loopback modes Loopback mode 1 2 5 7 8 9 Description Port Loopback (loopback plugs) External Serializer/Deserializer (SerDes) loopback Internal (parallel) loopback (indicates no external equipment) Back-end bypass and port loopback Back-end bypass and SerDes loopback Back-end bypass and internal loopback Troubleshooting a marginal link 1. Run D_Port tests. 2. Enter the portErrShow command. 3. Determine if there are a relatively high number of errors (such as CRC errors or ENC_OUT errors), or if there are a steadily increasing number of errors to confirm a marginal link. Sample the data every 5 minutes until you see the counters increment. ∙ The frames tx and rx are the number of frames being transmitted and received. ∙ The crc_err counter are frames with CRC errors. If this counter goes up, then the physical path should be inspected. Check the cables to and from the switch, patch panel, and other devices. Check the SFP by swapping it with a known good working SFP. If you see this issue on an 8 Gbps blade, use the portCfgFillWord command to reduce EMI. ∙ The crc_g_eof counter are frames with CRC errors and a good EOF. The first port detecting a CRC error marks the frame with a bad EOF and passes the frame on to its destination. Subsequent ports in the path also detect the CRC error and the crc_err counter increments on these ports. However, because the first port marked the frame with a bad EOF, the good EOF counter on the subsequent ports does not increment. The marginal link associated with the port with an increasing good EOF counter is the marginal link and the source of the errors. ∙ The enc_out are errors that occur outside the frame and usually indicating a bad primitive. To determine if you are having a cable problem, take snapshots of the port errors by using the portErrShow command in increments of 5 to 10 minutes. If you notice the crc_err counter go up, you have a bad or damaged cable, or a bad or damaged device in the path. NOTE ICLs see enc_out errors when ports on one side of the link are disabled. ∙ The disc_c3 errors are discarded class 3 errors, which means that the switch is holding onto the frame longer than the hold time allows. One problem this could be related to is ISL oversubscription. switch:admin> porterrshow frames enc crc crc too too bad enc disc link loss loss frjt fbsy tx rx in err g_eof shrt long eof out c3 fail sync sig Brocade Fabric OS Troubleshooting and Diagnostics Guide 42 53-1004126-01

Section	Page
Brocade Fabric OS Troubleshooting and Diagnostics Guide	1
Preface	7
Document conventions	7
Text formatting conventions	7
Command syntax conventions	7
Notes, cautions, and warnings	8
Brocade resources	8
Contacting Brocade Technical Support	8
Brocade customers	8
Brocade OEM customers	9
Document feedback	9
About This Document	11
Supported hardware and software	11
Brocade Gen 5 (16-Gbps) fixed-port switches	11
Brocade Gen 5 (16-Gbps) DCX 8510 Directors	11
Brocade Gen 6 fixed-port switches	11
Brocade Gen 6 Directors	12
What's new in this document	12
Introduction	13
Troubleshooting overview	13
Network Time Protocol	13
Most common problem areas	13
Questions for common symptoms	14
Gathering information for your switch support provider	17
Setting up your switch for FTP	17
Using the supportSave command	17
Changing the supportSave timeout value	18
Capturing output from a console	18
Capturing command output	19
Building a case for your switch support provider	19
Basic information	19
Detailed problem information	20
Gathering additional information	21
General Troubleshooting	23
Licenses	23
Time	23
Frame Viewer	23
Switch message logs	24
Switch boot	25
Rolling Reboot Detection	25
Reboot classification	25
Restrictions	26
Collecting limited supportSave output on the Rolling Reboot Detection	27
FC-FC routing connectivity	27
Generating and routing an ECHO	27
Superping	29
Restrictions	31
Routing and statistical information	32
Performance issues	33
Connectivity	35
Port initialization and FCP auto-discovery process	35
Link issues	36
Connection problems	37
Checking the physical connection	37
Checking the logical connection	37
Checking the Name Server	38
Link failures	39
Determining a successful speed negotiation	39
Checking for a loop initialization failure	40
Checking for a point-to-point initialization failure	40
Correcting a port that has come up in the wrong mode	41
Marginal links	41
Troubleshooting a marginal link	42
Device login issues on Fabric switch	43
Pinpointing problems with device logins	44
Device login issues on Access Gateway	45
Media-related issues	46
Testing the external transmit and receive path of a port	46
Testing the internal components of a switch	46
Testing components to and from the HBA	47
Segmented fabrics	47
Reconciling fabric parameters individually	48
Downloading a correct configuration	48
Reconciling a domain ID conflict	48
Reconciling incompatible software features	50
Configuration	51
Configuration upload and download issues	51
Gathering additional information	53
Messages captured in the logs	54
Brocade configuration form	54
Firmware Download Errors	55
Blade troubleshooting tips	55
Firmware download issues	56
Troubleshooting with the firmwareDownload command	58
Gathering additional information	59
USB error handling	59
Considerations for downgrading firmware	59
Preinstallation messages	60
Blade types	61
Firmware versions	61
Platform	62
Routing	62
Security	63
Passwords	63
Password recovery options	63
Device authentication	64
Protocol and certificate management	64
Gathering additional information	65
SNMP	65
Gathering additional information	66
FIPS	66
Virtual Fabrics	67
General Virtual Fabrics troubleshooting	67
Fabric identification issues	68
Logical Fabric issues	68
Base switch issues	68
Logical switch issues	69
Switch configuration blade compatibility	71
Gathering additional information	71
ISL Trunking	73
Link issues	73
Buffer credit issues	74
Getting out of buffer-limited mode	74
Zoning	75
Overview of corrective action	75
Verifying a fabric merge problem	75
Verifying a TI zone problem	75
Segmented fabrics	76
Zone conflicts	77
Resolving zoning conflicts	78
Correcting a fabric merge problem quickly	78
Changing the default zone access	79
Editing zone configuration members	79
Reordering the zone member list	79
Checking for Fibre Channel connectivity problems	80
Checking for zoning problems	81
Gathering additional information	81
Diagnostic Features	83
Fabric OS diagnostics	83
Diagnostic information	83
Power-on self-test	84
Disabling POST	85
Enabling POST	85
Switch status	85
Viewing the overall status of the switch	86
Displaying switch information	86
Displaying the uptime for a switch	87
Using the spinFab and portTest commands	88
Debugging spinFab errors	88
Link errors	89
Tx/Rx errors	89
Clearing the error counters	90
Enabling a port	90
Disabling a port	90
Port information	90
Viewing the status of a port	90
Displaying the port statistics	91
Displaying a summary of port errors for a switch	92
Equipment status	93
Checking the temperature, fan, and power supply	93
Checking the status of the fans	94
Checking the status of a power supply	94
Checking temperature status	94
System message log	95
Displaying the system message log with no page breaks	95
Displaying the system message log one message at a time	95
Clearing the system message log	96
Port log	96
Viewing the port log	96
Syslogd configuration	97
Configuring the host	97
Configuring the switch	98
Specifying syslogd hosts	98
Setting the facility level	98
Removing a syslogd host from the list	99
Automatic trace dump transfers	99
Specifying a remote server	99
Enabling the automatic transfer of trace dumps	99
Setting up periodic checking of the remote server	99
Saving comprehensive diagnostic files to the server	100
Multiple trace dump files support	100
Auto FTP support	100
Trace dump support	101
Switch Type and Blade ID	103
Hexadecimal Conversion	105
Hexadecimal overview	105
Example conversion of the hexadecimal triplet Ox616000	105

Match case Limit results 1 per page

The

portLoopbackTest

command is used to verify the functional operation of a path on a switch. This test sends frames from a given

port’s transmitter and loops them back into the same port’s receiver. The loopback is done at the parallel loopback path. The path

traversed in this test does not include the media or the fiber cable.

Only one frame is transmitted and received at any given time. An external cable is not required to run this test. The port LEDs flicker

green rapidly while the test is running.

Table 5

shows the different loopback modes you can use when using

portLoopbackTest

to test a marginal link.

TABLE 5

Loopback modes

Loopback mode

Description

Port Loopback (loopback plugs)

External Serializer/Deserializer (SerDes) loopback

Internal (parallel) loopback (indicates no external equipment)

Back-end bypass and port loopback

Back-end bypass and SerDes loopback

Back-end bypass and internal loopback

Troubleshooting a marginal link

Run D_Port tests.

Enter the

portErrShow

command.

Determine if there are a relatively high number of errors (such as CRC errors or ENC_OUT errors), or if there are a steadily

increasing number of errors to confirm a marginal link. Sample the data every 5 minutes until you see the counters increment.

∙

The

frames tx

and

are the number of frames being transmitted and received.

∙

The

crc_err

counter are frames with CRC errors. If this counter goes up, then the physical path should be inspected. Check

the cables to and from the switch, patch panel, and other devices. Check the SFP by swapping it with a known good

working SFP.

If you see this issue on an 8 Gbps blade, use the

portCfgFillWord

command to reduce EMI.

∙

The

crc_g_eof

counter are frames with CRC errors and a good EOF. The first port detecting a CRC error marks the frame

with a bad EOF and passes the frame on to its destination. Subsequent ports in the path also detect the CRC error and the

crc_err counter increments on these ports. However, because the first port marked the frame with a bad EOF, the good

EOF counter on the subsequent ports does not increment. The marginal link associated with the port with an increasing

good EOF counter is the marginal link and the source of the errors.

∙

The

enc_out

are errors that occur outside the frame and usually indicating a bad primitive. To determine if you are having a

cable problem, take snapshots of the port errors by using the

portErrShow

command in increments of 5 to 10 minutes. If

you notice the crc_err counter go up, you have a bad or damaged cable, or a bad or damaged device in the path.

NOTE

ICLs see enc_out errors when ports on one side of the link are disabled.

∙

The

disc_c3

errors are discarded class 3 errors, which means that the switch is holding onto the frame longer than the hold

time allows. One problem this could be related to is ISL oversubscription.

switch:admin> porterrshow

frames

enc

crc

too

bad

enc disc link loss loss frjt fbsy

err g_eof shrt long eof

out c3

fail sync sig

============================================================================

Connectivity

Brocade Fabric OS Troubleshooting and Diagnostics Guide

53-1004126-01