MicroBooNE is proposing to delete "version 5" run 3 swizzled TPC raw data taken after Dec. 1, 2017. Refer to the Run 3 Data web page. Note that "version 6" swizzled TPC raw data is available for most of the deleted data.
As of Sunday, Sept 9 at 9:03 pm, there were 58 blank tapes available at Fermilab. The burn rate for tape during the month of August 2018 was 33 tapes per week. The capacity of a tape is 8-10 TB depending on efficiency of file size and packing on the tape.
There is currently no plan for tapes deleted by an experiment to by reserved for exclusive use by that experiment. Tapes deleted by CMS, MicroBooNE, NOvA, etc would go back into the common pool for use by all experiments.
A proposal has been put in place and can be found on the following google doc: https://docs.google.com/document/d/1-aO7OK3V3_WzvnQpwyOe3Hj-x_szFbTxir-dO2G4ics/edit?usp=sharing. In summary, MicroBooNE has 10 days of storage on evb at our current trigger rate, and 2 months on other DAQ servers. Using other DAQ servers would require significant work from the production and operations team to move and store data appropriately. We can extend our disks' lifetime by a factor of x3 by keeping all beam events and giving up EXT triggers, but this starts to impact our physics.