I noticed this has only 1 and 2 star ratings after bumping into this issue myself, so I figured I would help out the original poster and others who are experiencing this issue.
Presumably, the original poster is intending to advise that we read the CUCM 10.0(1) Upgrade Guide, and view the Pre-Upgrade Tasks therein. These (the bullet points below) seem to be the salient options contained in that section. I used the "Free Common Space COP file" option to resolve my disk space issue and allow my upgrade. I found the .cop file in the following download area on CCO:
It is called: "VMware Disk Size Reallocation COP file: This COP file allows UCM VMs to increase the size of their vDisk(s) without requiring a system rebuild.
• Use the Cisco Log Partition Monitoring Tool to adjust the low and high watermarks to reduce the traces
and remove unnecessary log files. Cisco recommends that you adjust the low watermark value to 30,
and the high watermark value to 40. After the upgrade, you must restore the high and low watermarks
to their original values in order to avoid premature purging of traces. The default value for the high
watermark is 85. The default value for the low watermark is 80. For more information about using the
Cisco Log Partition Monitoring Tool, see the Cisco Unified Real-Time Monitoring Tool Administration
• Use the Disk Expansion COP file (ciscocm.vmware-disk-size-reallocation-<latest_version>.cop.sgn) to
expand the vDisk size if your virtual environment has additional available disk space. Ensure that you
review the Readme file that supports this COP file before you proceed.
• Use the Free Common Space COP file (ciscocm.free_common_space_v<latest_version>.cop.sgn). This
COP file removes the inactive side in the common partition to increase available disk space without
requiring a system rebuild. Ensure that you review the Readme file that supports this COP file before
• Manually remove outdated or unused firmware files from the TFTP directory. You can remove these
files using the TFTP File Management page in the OS Administration interface, or you can use the file
list tftp and file delete tftp commands from the command line interface.