Reflects the PBS storage tier redesign executed today (int-infra-proxmox#1):
primary `pct-backups` migrated from XFS-on-LVM to ZFS on pve1, replica
`pct-backups-replica` built on pve2 with daily pull-sync. Runbook 4 now
documents both tiers, the sync job verification flow, and the emergency
restore-from-replica procedure. Adds the three gotchas hit during build:
HA-managed PBS auto-restart, PBS API tokens needing ACL on both user
and token, and the recurring vmbr1 VXLAN MTU=1450 requirement.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>