Description

ACX5448 VMHost boot from alternate disk (Disk 2) whenever the primary disk (Disk1) fails or goes missing on the Next-Generation Routing Engine (NG-RE).

Symptoms

You will see the following alarm on the chassis: 
lab> show system alarms
3 alarms currently active
Alarm time Class Description
2023-09-17 09:55:22 BST Minor VMHost RE 0 Disk 1 Missing
2023-09-17 09:55:20 BST Minor VMHost 0 Boot from alternate disk

From the below output, you can see the current boot disk as Secondary:

> show vmhost version
Current root details,          Device sdb, Label: jrootp_S, Partition: sdb3
Current boot disk: Secondary
Current root set: p
UEFI   Version: REH_P_MTR1_00.30.07
Secondary Disk, Snapshot Time: Fri Jul 14 10:29:09 IST 2023
Version: set p
VMHost Version: 5.2279
VMHost Root: vmhost-x86_64-20.2R3-S1-20210430_0731_builder
VMHost Core: vmhost-core-x86-64-20.2R3-S1.3
kernel: 4.8.28-rt10-WR9.0.0.24_ovp
Junos Disk: junos-install-mx-x86-64-20.2R3-S1.3
Version: set b
VMHost Version: 5.2279
VMHost Root: vmhost-x86_64-20.2R3-S1-20210430_0731_builder
VMHost Core: vmhost-core-x86-64-20.2R3-S1.3
kernel: 4.8.28-rt10-WR9.0.0.24_ovp
Junos Disk: junos-install-mx-x86-64-20.2R3-S1.3

 

Solution

1. The minor alarm "VMHost RE 0 Disk 1 Missing" appears when disk 1 in the Routing Engine 0 is missing. This alarm is caused when the disk is actually missing in the Routing Engine or the disk has turned defective.

2. Check the Routing Engine and check if the missing disk gets detected. The following CLI command can be used to confirm disk is missing for the affected Routing Engine: 
>show vmhost hardware

3. If the disk is missing, then insert a healthy disk. If the disk exist and it is faulty, the way to recover the faulty disk is by running: 
>request vmhost snapshot 

>request system snapshot recovery partition
warning: All existing data on the target media will be lost
Proceed ? [yes,no] (no) yes

Creating snapshot on target disk from current boot disk ...
Primary disk is recovered now. Please issue "request vmhost reboot" to boot from the primary disk.
Software snapshot done

4.Reboot the RE by using the command "request vmhost reboot" 

5. If the alarm still issue persists, try inserting a working disk.

6. Replace the Routing Engine if the above recovery does not help by contacting Support.

Modification History

Init Draft