# sbo-testbuild storage layout, /etc/fstab on the docker host.
#
# Copyright (C) 2026 Danilo M. <danix@danix.xyz>
# GPLv2 only; see LICENSE.
#
# Reference copy of the two entries this build system depends on. Nothing
# reads this file; it is recorded so the layout survives a lost VM, because
# where these live is not a detail. Getting it wrong is what broke the
# nightly builds for ten days.
#
# The UUID below is this host's; use your own (`blkid /dev/sdb1`).

# ---------------------------------------------------------------------------
# Docker data: its own disk
# ---------------------------------------------------------------------------
# Build scratch space wants room to breathe. Exporting the -current full image
# writes roughly its own size (~33G) transiently, on top of the images already
# resident, so this volume is sized for the peak and not the steady state.
# Everything on it is reproducible from the mirror, so it is excluded from
# vzdump.
UUID=0e5d008d-0ee0-41bc-9222-aedba1e088d0  /var/lib/docker  ext4  defaults  0  2

# ---------------------------------------------------------------------------
# Registry store: NOT on the docker disk
# ---------------------------------------------------------------------------
# The registry's blob store used to be a bind mount from the docker disk
# (/var/lib/docker/registry-data). That put ~25G of permanently-resident data
# on the same volume as the transient build peak, and the two competed: the
# registry grows with every push, the build needs headroom at 03:20, and the
# build lost. Moved to the system disk on 2026-09-22, which had 49G idle.
#
# Keep them separate. The registry is small, static and I/O-light; the build
# disk is large, churning and latency-insensitive. Sharing one volume couples
# a slow leak to a hard failure.
#
# If this host's backups cover the system disk, exclude /opt/registry-data:
# the contents are reproducible by re-pushing the images.
#
# Moving it is not just an fstab edit. dockerd caches the mount in its own
# namespace, so after remounting you must restart the daemon and recreate the
# registry container, or pushes keep silently landing on the old disk. Verify
# with:  grep ' /var/lib/registry ' /proc/$(docker inspect registry \
#            --format '{{.State.Pid}}')/mountinfo
# and check the device is the system disk, not the docker one.
/opt/registry-data  /opt/sbo-testbuild/registry  none  bind  0  0

# ---------------------------------------------------------------------------
# Booting: LILO, and it needs re-running by hand
# ---------------------------------------------------------------------------
# This host boots BIOS/legacy with LILO in the MBR of /dev/sda. GRUB is also
# installed, but only as EFI binaries under /boot/efi, and the firmware never
# boots in EFI mode, so they are inert. There is no ambiguity about which
# bootloader runs; there is just an unused one lying around.
#
# LILO maps the kernel by physical block address, so the map goes stale
# whenever the blocks move. Run `lilo -v` after:
#
#   * installing or replacing a kernel or initrd (the usual case)
#   * editing /etc/lilo.conf
#   * moving or defragmenting /boot
#
# Forgetting leaves an unbootable machine that looks fine until it reboots,
# which on a headless VM means a console session to recover. `lilo -t -v`
# tests without writing, and re-running `lilo -v` when nothing changed is
# harmless, so when in doubt, run it.
#
# Editing the entries above does NOT need it: mounts are userspace, applied
# long after the kernel loads, and the root device is unchanged.