This article describes SIB Fault on QFX10000 - Fault during power up - Asic init failed 

An alarm will appear indicating SIB Fault.

> show chassis alarms no-forwarding

Alarm time         Class Description

2023-05-14 18:26:43 UTC Major SIB 4 Fault

Check the output of "show chassis sibs" and the log messages to understand the cause of failure. 

> show chassis sibs
Slot 4 information:
 State                Fault
 Reason               Fault during power up
 Fabric links         Unused
 Errors               None

May 14 18:24:37 hostname-re1 spmb1 Failed to detect SIB[4] PLX device @ /sys/bus/pci/devices/0000:26:00.0

May 14 18:26:43 hostname-re1 spmb1 SIB[4] PLX device bringup failed!!!

May 14 18:26:43 hostname-re1 chassisd[7370]: CHASSISD_FM_SIB_ERROR: Fabric management error for SIB 4: SIB init failed; setting to FAULT (Fault during power up)

May 14 18:26:43 hostname-re1 alarmd[7371]: Alarm cleared: SIB id=134218868, color=YELLOW, class=CHASSIS, reason=SIB 4 Not Online

May 14 18:26:43 hostname-re1 chassisd[7370]: CHASSISD_SNMP_TRAP7: SNMP trap generated: Fru Failed (jnxFruContentsIndex 15, jnxFruL1Index 5, jnxFruL2Index 0, jnxFruL3Index 0, jnxFruName SIB 4, jnxFruType 9, jnxFruSlot 4)

May 14 18:26:43 hostname-re1 craftd[7372]: Receive FX craftd clear alarm message: color: Minor class: 100 slot: 4

May 14 18:26:43 hostname-re1 craftd[7372]: Minor alarm cleared, SIB 4 Not Online

May 14 18:26:43 hostname-re1 alarmd[7371]: Alarm set: SIB id=16778356, color=RED, class=CHASSIS, reason=SIB 4 Fault

May 14 18:27:07 hostname-re1 spmb1 SIB[4] Asic init failed. Marking the SIB faulty!

"Fault during power up" is seen in the o/p fo "show chassis sibs". The logs messages indicate that the "Asic init failed" 

This indicates a potential hardware failure. The SIB will need replacing.