diff --git a/scripts/ci/docker-prune.sh b/scripts/ci/docker-prune.sh
index e3a0c6be..b7feac39 100644
--- a/scripts/ci/docker-prune.sh
+++ b/scripts/ci/docker-prune.sh
@@ -19,7 +19,13 @@ export PATH=/usr/bin:/bin:/usr/local/bin:$PATH
 CACHE_DIR=${CACHE_DIR:-/home/runner/gitea-runner-fleet/cache}
 CAP_MB=${CAP_MB:-20000}                 # clear the cache store once it exceeds ~20 GB
 BURST_PCT=${BURST_PCT:-80}              # full clear once the disk is this % full
-MIN_FREE_GB=${MIN_FREE_GB:-45}          # ...or this little is left, whichever trips first
+MIN_FREE_GB=${MIN_FREE_GB:-60}          # ...or this little is left, whichever trips first.
+                                        # 60, not 45: this has to fire BEFORE the disk is
+                                        # actually tight, because the clear only reclaims idle
+                                        # images (~18 G) while three concurrent jobs can eat
+                                        # the remainder inside one poll interval. Measured
+                                        # 2026-07-29: zero burst clears fired in six hours
+                                        # while deb still died of ENOSPC between polls.
 
 # 1) Routine: trim aged images / build cache / stopped containers. sha-<commit> tags aren't
 #    dangling, so -a is required. until=2h, not 6h: on a busy day every image is younger than six
diff --git a/scripts/ci/docker-prune.timer b/scripts/ci/docker-prune.timer
index 5e98482f..0035af85 100644
--- a/scripts/ci/docker-prune.timer
+++ b/scripts/ci/docker-prune.timer
@@ -1,8 +1,11 @@
-# Runs docker-prune.service every 10 min. It was every 30, and that is how the burst guard never
-# fired once: three concurrent Rust builds fill the disk and drain it again well inside a 30-minute
-# window, so the poll kept landing on a healthy `df` while jobs died of ENOSPC in between. (An arch
-# build failed with `as: BFD assertion fail` — assembler noise for "can't write, No space left on
-# device" — and by the time anyone looked, the disk was back to 37% used.)
+# Runs docker-prune.service every 2 min. It was 30, then 10, and BOTH still lost the race: measured
+# over six hours on 2026-07-29 the burst guard fired zero times while deb died of ENOSPC between
+# polls, because three concurrent Rust builds fill the disk and drain it again inside the interval.
+# (The arch symptom is `as: BFD assertion fail` — assembler noise for "can't write, No space left on
+# device" — and by the time anyone looks, df is back under 40% used.)
+#
+# Every 2 min is affordable: the script is a handful of docker calls and no-ops in about a second
+# when there is nothing to reclaim.
 #
 # Ten minutes is a backstop, not the fix. The fix was capacity: the LXC rootfs went 123 G -> 175 G
 # on 2026-07-29 (`pct resize 116 rootfs +50G` on home-node-1), which is what actually gives three
@@ -10,11 +13,11 @@
 # Persistent=true catches up after downtime. Install: see the header of docker-prune.service.
 
 [Unit]
-Description=Run docker-prune every 10 min (CI runner disk hygiene + cache cap + burst guard)
+Description=Run docker-prune every 2 min (CI runner disk hygiene + cache cap + burst guard)
 
 [Timer]
-OnCalendar=*:0/10
-RandomizedDelaySec=30
+OnCalendar=*:0/2
+RandomizedDelaySec=10
 Persistent=true
 
 [Install]