The Spectrum install provides a mysql optimization script: $SPECROOT/SS/DDM/script/db_optimize.pl
When this script is run in 22.2.5 and above, it may cause mysql to fill the tmp files and run the disk out of space.
Spectrum and mysql 8
There was a change in mysql 8 indexing that the script was not accounting for.
This is resolved in patch D228a for 22.2.5 and will be resolved in 23.3.6 once released.