Description

This article explains the meaning of the alarms VMHost RE 0 disk1 and disk2 File System Errors that may be seen on MX and PTX routers and indicates if any actions need to be taken.

 

 

Symptoms

Alarm seen on the device: 

root> show system alarms
2 alarms currently active
Alarm time               Class  Description
2019-08-05 12:41:41 UTC  Minor  VMHost RE 0 Disk 1 File System Errors
2019-08-05 12:41:41 UTC  Minor  VMHost RE 0 Disk 2 File System Errors

This alarm is seen when there is a file system error on the disk of the Routing Engine. 

Routing Engine 0 REV 05   750-072925   XXXXXX          RE-S-2X00x6
Routing Engine 1 REV 05   750-072925   XXXXXX          RE-S-2X00x6

Solution

Cause : NG-RE (Next-Generation Routing Engine)  has two SSDs: SSD1 and SSD2. The first disk connected with channel 0 is the primary disk. The other disk is considered as a backup. There are two sets of software boot images on the primary disk. You boot with one set, and when an upgrade is needed, it switches to use the other set. Similarly, on the rollback, you switch to the other set.

In the alarm VMHost RE x Disk y File System Errors , x=0 for RE0 and 1 for RE1 and y=1 for disk 1 and 2 for disk 2.

 

  • Scenario A: If a file system error is detected on one of the disks, recovery can be performed using the alternate (healthy) disk.
    FYI: 2019-08-05 12:41:41 UTC  Minor  VMHost RE 0 Disk 1 File System Errors


To clear this alarm, the affected Routing Engine should be booted from the healthy disk. Once booted, the impacted disk can be recovered using the following command: (Perform in MW)


 


 Command  :  request vmhost snapshot




If the state of the primary disk (disk1) is good and the backup disk (disk2) has to be recovered, use the    request vmhost snapshot    command to recover the backup disk, assuming that the RE is booted from the primary disk. If the state of the secondary disk is not known or the file systems in the disk are not in a consistent state, then include the partition option in the command, that is,    request vmhost snapshot partition.


 


If the state of the backup disk (disk2) is good and the primary disk (disk1) has to be recovered, use the    request vmhost snapshot recovery    command to recover the primary disk, assuming that the RE is booted from the backup disk. If the state of the primary disk is not known or the partition tables are in bad condition, then include the partition option in the command, that is,    request vmhost snapshot recovery partition  . 


 


To boot from the desired disk, execute the    request vmhost reboot { disk1, disk2}     command.


 


  • Scenario B: If both disks on the Routing Engine are experiencing file system errors, recovery from the alternate disk is not possible. In such cases, the Routing Engine must be accessed using a console connection, and perform following to steps to clear the alarms:


2019-08-05 12:41:41 UTC  Minor  VMHost RE 0 Disk 1 File System Errors
2019-08-05 12:41:41 UTC  Minor  VMHost RE 0 Disk 2 File System Errors

Schedule a maintenance window (MW) to perform the following actions:


  1. 

    • Restart RE0, which will also restart any related daemons. If the issue is caused by an underlying system problem, this step may help resolve it.
    • Please reach out to JTAC, who will verify the issue and proceed to open an RMA if necessary.
    

Modification History
2021-08-20: Modified article to include information about x and y in show system alarm
2025-06-24: Adding the NG-RE correction on Solution Tab and adding the output on symptoms
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