I've seen something similar to this.

We sometimes have clients that want to run a "convert archive"  and most of
the time it's not a problem.  We have had instances where the convert has
run for 3 days without problems.  We had one case where the convert archive
and expiration clashed and the db log filled.  We were unable to cancel the
expiration.  It crashed the TSM server.

We try not to run too make housekeeping processes at the same time because
of this.