ADC upgrade is failing due to /var folder filling. Checking the /var folder we notice that /var/partitions is taking up a lot of the space. Looking into this further we can see there are many .pdb files taking up space within directory /var/partitions/<PartitionName>/nscollectRRD.
The .pdb files can be manually deleted to create space within the /var directory.
Note: For an upgrade to be successful we require minimum of 70% space available on ADC.