I just wanted to put a big +1/upvote/shout out for this idea.
We too want to be able to see failed workflows – but discard successful ones. Similarly, it would really help for KNIME Server to be able to discard really old workflows (in some cases, really old means older than a few days, in other cases, that’s a month). We recently had a problem where KNIME Server just stopped working because the disk was full because we have no middle ground, and we found it was these old workflows that filled up our disk.
As is, because KNIME Server cannot discard appropriate workflows, KNIME Server is not truly self managing because we have to go in and check it regularly to make sure that it hasn’t used up our disk (which is large, but running several workflows many times can fill it up over time).