Once the SARINIT DBTHRESH=... parameter is reached, whenever a new report is collected, the utilization amount is checked and a message is put out.
The message will be put out every time something is archived to the database.
The parameter is defaulted to 80, so at 80% utilization, a message will be put out for every sysout collected.
It is not recommended, but you may raise the threshold percentage by changing the SARINIT DBTHRESH=... parameter and recycling the SARSTC task, to see fewer messages.
Issuing "/F sarstc,DUMP" is requesting the on-demand occurrence of a View standard backup to the database, which is a temporary remedy to reclaiming database space.
Please note that the running of a View backup may not necessarily free up any space, however, reports are still collecting during that time.
A tendency towards "storage creep", which occurs with the passage of time, usually results in the best long-term remedy being to add some space (via SARDBASE ADDDS DATA (or INDEX)).