As Prime is not able to start and you need to use it for 2 months, I would suggest installing a new version of 3.0 and restoring a backup to it.  TAC is available to help in this regard, just have to open a case.  The install takes about 3 hours and ...

Check these things:   Were changes made to the Data Retention on Prime? PI > Administration > System Settings > Data RetentionDefaults are attached in the screenshot. Setting the 3rd field to less than a year is suggested to decrease the database siz...

Check for Space issues: Login to Prime via SSHtype in 'shell'enter credentials for admin - this will give you access to linuxtype in 'df -h'look at the entries to see if any are 100% full or getting close - specifically look at /varif /var is full, e...