platform/docs/adr/0005-zfs-per-customer.md
Bart Van Geyt e5ff798dd4 Refine to nested customer -> site model
Adopt a two-level ownership model: a customer owns many sites, with
isolation/containers/DB/backup at the site level and grouping (one SFTP
login, recursive backup, billing, bulk delete) at the customer level.

- 03-naming-conventions: rewritten for customer/site ids and slug =
  <customer>-<site>; nested ZFS, per-customer SFTP chroot, deployments
  mirror the nesting.
- Propagated paths through docs 01, 04, 05, 06, 07 and deployments/README.
- ADR 0005 retitled/updated to per-site datasets nested under customer.
- architecture-plan.md: note pointing to doc 03 as authoritative on naming.

Clarifies subdomains: same-app subdomains are aliases on one site; a
separate-app subdomain is its own isolated site under the same customer.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-07-07 12:37:39 +02:00

1.3 KiB

ADR 0005 — ZFS dataset per site (nested under customer)

Status: Accepted

Context

Backups must be cheap, integrity-checked, and restorable per customer without touching neighbours. ZFS offers checksummed integrity, cheap copy-on-write snapshots, and incremental zfs send.

Decision

Create a ZFS dataset per site, nested under the owning customer (tank/customers/<customer>/<site>/web), holding only the web root. The customer level is a grouping parent enabling recursive snapshots and a single SFTP chroot; the site level is the isolation/restore unit. Docker image/layer storage and the MariaDB datadir live on separate platform datasets. Site web data is bind-mounted into containers from its dataset.

Consequences

  • Snapshot and zfs send operate at the customer granularity — restore one customer independently.
  • Data integrity via checksums; cheap frequent snapshots.
  • Keeping the dataset to web files only (no logs, no DB dumps) means an unchanged site produces a near-empty incremental, keeping offsite send cheap — the explicit reason logs and DB dumps are stored elsewhere (ADR 0006).
  • Ties the platform to a ZFS-capable host (OpenZFS on Linux); not portable to arbitrary cloud block storage without rework.