Description

The "BIST: Memory Error" message reports a hardware issue.


This is a Troubleshooting Article for a PFE ASIC Syslog Event.
To view other documented syslog events related to XMCHIP, XLCHIP, MQCHIP, LUCHIP, EACHIP, and PECHIP, see KB31893 - Master Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] .

.

Symptoms

RamBIST test means that Memory Bulit-in self test and if any test fail below error will be reported and this can happen for any ASIC in the system like LU/XR.. etc below log is reported for LU-Chip


<host>   <FPC#> :RamBIST:LU-CHIP[1] DDR 0 BIST: Memory Error
<host>   <FPC#> :RamBIST:LU-CHIP[1] DDR 0 BIST: Test Name:Unique Address (Bottom-Up)
<host>   <FPC#> :RamBIST:LU-CHIP[1] DDR 0 BIST: Error Count: 1

<host>   <FPC#> :LUCHIP(4): Bist RLDRAM 1 failed
<host>   <FPC#> :RamBIST:LU-CHIP[4] RLDRAM 1 BIST: Error Address: Raw: 0x00000000014909d8 Cell: 0x0000000000052427
<host>   <FPC#> :RamBIST:LU-CHIP[4] RLDRAM 1 BIST: Expected Data: 0x000000000000004000d000300028000a
<host>   <FPC#> :RamBIST:LU-CHIP[4] RLDRAM 1 BIST: Vector Data:   0x00000000000000000000000020000000

Indications:

  • This memory error upon BIST failure will prevent the FPC from coming online

 

Solution

The cause is due to a memory error detected at POST (Power on Self Test) one FPC does initialize all components. The LUCHIP initialization fails while booting up the FPC  due to BIST errors.

 

{DIDYOUKNOWSERVICENOWTOKEN.EN_US}

Perform these steps to determine the cause and resolve the problem (if any).  Continue through each step until the problem is resolved.

  1. Collect the show command output.

    {SYSLOGSERVICENOWTOKEN.EN_US}

    Capture the output to a file (in case you have to open a technical support case). To do this, configure each SSH client/terminal emulator to log your session.

    show log messages
    show log chassisd
    start shell network pfe <fpc#>
    show nvram
    show syslog messages
    exit

  2. Analyze the show command output.

In the 'show log messages', review the events that occurred at or just before the appearance of the "BIST: Memory Error" message. Frequently these events help identify the cause.

  • Offline the FPC in case it still came online.

    • Run the CLI command ‘ request chassis fpc slot # offline ’,
      For more information on the command, see  request chassis fpc .

  • ​Contact your technical support representative immediately to RMA the card regardless of error rate.

This article is indexed in  KB31893 - Primary Index of Articles for Troubleshooting PFE ASIC Syslog Events [juniper.net] tag LUCHIPTSG


Tip: When looking at an event in the logs, it is important to focus on the first error message in a collection of syslog messages. The first error message is usually the cause of all the follow-on error messages. The follow-on collateral damage error messages can be ignored.

 

Modification History

2022-10-21 Mark KB as public - missing from previous review
2019-10-14: Article reviewed for accuracy; no changes required.