Backup failure: Error: -1 - chown changing ownership... Read-only file system (4036313)

Backup failure: Error: -1 - chown changing ownership... Read-only file system

Backup using Virtual Appliance fails with: Error: -1 - chown: changing ownership of '/root/vzva/201409250900/backup': Read-only file system chown: changing ownership of '/root/vzva/201409250900/vmmutex': Read-only file system chown: changing ownership of '/root/vzva/201409250900/vixclean': Read-only file system chown: changing ownership of '/root/vzva/201409250900/catalog': Read-only file system chown: changing ownership of '/root/vzva/201409250900/dirlist': Read-only file system chown: changing ownership of '/root/vzva/201409250900/vddkd.so': Read-only file system chown: changing ownership of '/root/vzva/201409250900/ionfs.so': Read-only file system chown: changing ownership of '/root/vzva/201409250900/ioosftp.so': Read-only file system chown: changing ownership of '/root/vzva/201409250900/sha1.so': Read-only file system chown: changing ownership of '/root/vzva/201409250900/abm': Read-only file system chown: changing ownership of '/root/vzva/201409250900/activeblock': Read-only file system chown: changing ownership of '/root/vzva/201409250900/metadata': Read-only file system chown: changing ownership of '/root/vzva/201409250900/vixclone': Read-only file system chown: changing ownership of '/root/vzva/201409250900/replicate': Read-only file system chown: changing ownership of '/root/vzva/201409250900/ioddb.so': Read-only file system chown: changing ownership of '/root/vzva/201409250900/initdirs': Read-only file system chown: changing ownership of '/root/vzva/201409250900/libvzvfr.so': Read-only file system chown: changing ownership of '/root/vzva/201409250900/ssh': Read-only file system chown: changing ownership of '/root/vzva/201409250900/iorofs.so': Read-only file system chown: changing ownership of '/root/vzva/201409250900/remotereplicate': Read-only file system chown: changing ownership of '/root/vzva/201409250900/lzo.so': Read-only file system chown: changing ownership of '/root/vzva/201409250900/restore': Read-only file system chown: changing ownership of '/root/vzva/201409250900/

Something has happened that the File System is in a Read Only Mode.

Reboot the Virtual Appliance and try the backup again.  It should succeed.