Over time (about 8 months) the full backup duration time increases from 0,5 to 4,75 hours and with that seeing the average throughput decreases from above 300 Gb/hr to about 35 Gb/hr.
Recently the Oracle instance restarted spontaneously as the full backup tried to start. After this the backup time and throughput are performing well again.
Oracle 12.1.0.2, Windows 2012 R2, Commvault 11, size DB grow in this 8 months from 133 to 155 Gb.
What could have caused this performance decrease and more important are there ways to prevent this and monitor (of course, now we know we keep an eye on the statistics) or is this a known issue?