Nectar Research Cloud monash-01 availability zone is undergoing a major infrastructure upgrade as a part of the cloud's hypervisor decommissioning and replacement.
During the migration process, we have encountered filesystem related issues on the secondary ephemeral drive at some of the instances.
We have unmounted non-root partitions on suspected VMs after the migration and notified users of the recovery process
What to do if you are affected:
A quick remedy is to rescue the VM either through selecting the recovery mode in the GRUB Prompt
After logging into the root prompt, just comment the non-root partitions (for example: /dev/vdb) in /etc/fstab.
Reboot the instance and run fsck on the unmounted partitions to check the filesystem on the secondary ephemeral drive
You may want to emount the drive after fsck checks.
Sorry for the inconvenience caused.