In certain rare cases, enlarging the virtual disk, using the tools provided by the hypervisor, the disk becomes unmountable when using the Storage option in the Appliance Management (port 9443) to expand the partition on that disk.
This has been reported for the disk used for /var as the /vastorage.
A fix is available in the Filr 3.4.2 update, available over the update channels.
The underlying script that triggers the partition expansion had a non-matching version.
This cases in some cases that the partition was set larger the actual size of the disk.