cmd_prune_count's `log " Pruned: ..."` wrote to stdout, which the
caller captures via `pruned=$(cmd_prune_count)`. From 2026-04-16 onward
(7d retention kicked in), pruned snapshots polluted the captured value
with multi-line log text, breaking the Prometheus exposition format
on the metric push (`lvm_snapshot_pruned_total ${pruned}` → 400 from
Pushgateway). Snapshots themselves were always fine; only the metric
push silently failed for ~9 nights, eventually triggering
LVMSnapshotNeverRun (alert has 48h `for:`).
Fix: redirect the inner log call to stderr so cmd_prune_count's stdout
contains only the count. Also adopts `infra/scripts/lvm-pvc-snapshot.sh`
as the source-of-truth (was edited only on the PVE host) and updates
backup-dr.md to point at the .sh and document the scp deploy.
Deploy: scp infra/scripts/lvm-pvc-snapshot.sh root@192.168.1.127:/usr/local/bin/lvm-pvc-snapshot
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>