Users may see the "VMHost RE x Disk y Label Missing" minor alarm on a device running Junos OS when the labels on the disk, which refer to the set from which the Virtual Machine (VM) booted up, in the Routing Engine (RE) are missing.
This article explains that you can use the "echo" command to bring back the labels and clear the alarm.
The Routing Engine has two sets of disks, which are named SDa (Disk-1) and SDb (Disk-2). You can verify these disks by using the show chassis hardware details or the show vmhost hardware routing-engine both commands.
labroot@router-re0> show vmhost hardware routing-engine both re0: -------------------------------------------------------------------------- Compute cluster: router-re-cc Compute node: router-re-cn Hardware inventory: Item Capacity Part number Serial number Description DIMM 0 8192 MB VL31D1G63F-K0SE-JN 50044903 DDR3 1600 MHz DIMM 1 8192 MB VL31D1G63F-K0SE-JN 50044133 DDR3 1600 MHz DIMM 2 8192 MB VL31D1G63F-K0SE-JN 50044150 DDR3 1600 MHz DIMM 3 8192 MB VL31D1G63F-K0SE-JN 50044149 DDR3 1600 MHz Disk1 50.0 GB SFSA050GQ1AA2TO 000060153151A1000061 SLIM SATA SSD Disk2 50.0 GB SFSA050GM3AA2TO 000060157867B1000146 SLIM SATA SSD re1: -------------------------------------------------------------------------- Compute cluster: router-re-cc Compute node: router-re-cn Hardware inventory: Item Capacity Part number Serial number Description DIMM 0 8192 MB VL31D1G63F-K0SE-JN 49398543 DDR3 1600 MHz DIMM 1 8192 MB VL31D1G63F-K0SE-JN 49398503 DDR3 1600 MHz DIMM 2 8192 MB VL31D1G63F-K0SE-JN 49398526 DDR3 1600 MHz DIMM 3 8192 MB VL31D1G63F-K0SE-JN 49398517 DDR3 1600 MHz Disk1 50.0 GB SFSA050GQ1AA2TO 000060153151A1000041 SLIM SATA SSD Disk2 50.0 GB SFSA050GM3AA2TO 000060156705B1000227 SLIM SATA SSD
You may see the following minor alarms on the device when the labels (which refer to the set from which the VM booted up) on the disk in the RE are missing. Note that these alarms might be transient in nature and may be reported for one disk or both disks.
XX@XXXX> show chassis alarms 1 alarms currently active Alarm time Class Description xxxxx xxxx UTC Minor VMHost RE x Disk y Label Missing x is RE slot y is Disk slot (there are two disks on the RE).
In the "VMHost RE x Disk y Label Missing" alarm, "x" is 0 for RE0 and 1 for RE1 and "y" is 1 for disk 1 and 2 for disk 2.
Use the following command to get back the label for Disk-2, which is SDb.
<< Use request system snapshot and/or request vmhost snapshot partition (depending on the RE that is reporting the alarm) start shell user root vhclient -s lsblk echo 1 > /sys/class/block/sdb/device/delete dmsetup remove jvg_S-jlvmrootrw dmsetup remove jvg_S-jlvmjunos dmsetup remove jvg_S-jlvmvm dmsetup remove jvg_S-jlvmspare lsblk for host in /sys/class/scsi_host/*; do echo "host -> $host"; echo "- - -" > $host/scan; sleep 1; ls -l /dev/sd*;done
Note: Modify the command "echo 1 > /sys/class/block/sdb/device/delete" to "echo 1 > /sys/class/block/sda/device/delete" if Disk-1 (SDa) is reporting the alarm.
2022-09-13: Initial publication