Ran clean_failover_preservation.sh on a real fs ($HOME/tmp/xce-ha-deploy, ext4).
PAYLOAD run CONFIRMED bug-990 fixed live: standbys persist the leader's real
term (2) for the committed prefix; walcompare OK.
Harness fixes: robust failover detection (any post-kill CTRL_PRIMARY promotion,
45s settle) + a wait-for-commit-before-kill gate (jobsub returns on accept not
commit, so the prior harness raced replication vs kill).
That commit-wait gate exposed bug-991: on a STABLE cluster, jobs replicate to
all members (durable LSN 5) but committed_lsn pins at 1. Catch-up-delivered
entries don't advance the library commit_index, so task-2.4's ceiling
min(durable-majority, raft_commit_index) starves commit below the durable
majority. A real regression from the commit-source switch (2.4+3.3), invisible
to the steady-state-only unit tests.
Rongsong Shen
df4bc4f86a