Virtual machine went unresponsive and VHD is smaller than should be

We have a virtual machine that has been running over a year with SLES on it as a mail server.

Late yesterday night Central time the machine suddenly just stopped processing and all disk IO stopped.

The machine shows to be running with CPU activity but will not respond to SSH connections anymore.

We have shutdown the machine and the cloud service and did a capture and downloaded the VHD.  But looking at the storage the OS disk/VHD is under 5 GB, but it was originally one of the standard 30 GB ones.

The download of the VHD contains the config files and the root filesystem, but all the data in another filesystem is completely missing.

Any help or suggestions would be appreciated.

Thanks.