On a QFX5100 switch with Routing Engine FPGA version 7.1, JUNOS software might not successfully boot after a system power down event. In the case of a system boot failure, you will need to power cycle the switch to recover.
QFX5100 Routing Engine FPGA firmware 7.1 is vulnerable to a boot stuck issue upon any power shutdown. With the 7.1 FPGA firmware version, the CPU and PCIe initialization may not complete. This is an unpredictable and rare race condition that may happen during power up scenarios. FPGA version 7.4 resolves this issue. The trigger is un-deterministic and is seen in less than one in a hundred cold boots in lab testing with 7.1 FPGA firmware versions. There is no workaround for this issue. In case of a system reboot failure, you need to power cycle the switch. Refer PR 926940 . Current shipping QFX5100s will have the with newer FPGA versions. Previously shipped systems that have Routing Engine FPGA version 7.1 should be upgraded to the 7.4 FPGA version in a maintenance window. This is applicable to QFX5100-24Q , QFX5100-48S with 2 Management Ports ( 1C0, 1C1). This is not applicable to QFX5100-24Q , QFX5100-48S with 3 Management ports ( 2 C0, 1 C1) . Please refer Management Panel of QFX5100 Hardware guide. Please contact JTAC if the system is running RE FPGA version 7.1 for upgrade procedure.