docs(databases): reverting an HA cluster keeps the deleted nodes' volumes

[paulocsanz]

Reverting an HA cluster to standalone deletes the member services but deliberately keeps their volumes — a revert never destroys data. The volumes stay in the project, unattached, and keep counting toward storage billing, which undocumented reads as a resource leak (it has generated real support escalations).

Adds a short Reverting keeps every deleted node's volume paragraph to the Reverting to Standalone section of all three HA pages (Postgres, MySQL, Redis): what is kept and why, that it bills, that deleting the leftovers is safe once the standalone service is confirmed healthy, and that a later re-conversion provisions fresh suffixed volumes rather than reusing them.

Note: the major-version-upgrade revert keeps its swapped-out volume for the same reason, but there is no major-upgrade docs page yet to carry it — worth adding when that page lands.

[railway-app]

🚅 Deployed to the docs-pr-1325 environment in 🪄 *.railway.com

Service	Status	Web	Updated (UTC)
Docs Frontend	✅ Success (View Logs)	Web	Aug 31, 2026 at 2:56 am

7 services not affected by this PR

• Turnout
• devicons
• Frontend Redis
• Blog
• Meilisearch
• OG
• Geofeed

[rw-growth-check]

Growth check — AMH estimate

#1325 @ 86e81ba — advisory only. Judgment ranges, ≤2 significant figures; SEO and AEO legs are never summed (AMH_RULES v2.2, constants v2.3 (2026-08-06)).

Files considered:

• content/docs/databases/mysql-ha.md (modified)
• content/docs/databases/postgresql-ha.md (modified)
• content/docs/databases/redis-ha.md (modified)

SEO leg (Google surface)

0.5–1.7 visits/mo

AEO leg (AI assistants)

2.2–6.6 visits/mo

Gates

• SERP page type(s): /Article,/Article/Tutorial_or_Guide
• AI Overview present: absent
• Gated to zero: no
• Gauge topic: redis-and-supabase-hosting (matched)

Keyword candidates for the AMH panel

New (not yet curated) deploy/hosting-intent keywords found around this content — candidates to add to the panel/Gauge:

Keyword	US volume/mo	KD	Question
redis cluster high availability	10	—	no
mysql failover setup	0	—	no
redis high availability cluster	0	—	no
redis high availability sentinel cluster	0	—	no
high availability redis cluster	0	—	no
redis cluster high availability architecture	0	—	no

Caveats & verification stamps

• Subject may also span sibling topic(s): multi-region-failover-hosting — the AEO leg prices ONE topic; verify subject-matched prompts (gauge_get_prompt_answers) before summing sibling shares (AMH_RULES §3.10/§4).
• Current-traffic baseline (modified pages): /databases/mysql-ha: 33 pageviews, 25 visitors (2 AI-referred) over ~2mo; /deploy/mysql-ha: 6 pageviews, 3 visitors (0 AI-referred) over ~2mo; /databases/postgresql-ha: 151 pageviews, 116 visitors (2 AI-referred) over ~2mo; /databases/redis-ha: 60 pageviews, 51 visitors (2 AI-referred) over ~2mo; /deploy/redis-ha: 33 pageviews, 18 visitors (0 AI-referred) over ~2mo.
• Verification pass: PostHog rates are stamped person- vs event-level — visitors are person-level (uniqExact person_id), pageviews are event-level (AMH_RULES §5/§8).
• Verification pass: the AEO Δ is a labeled ASSUMPTION (+1pt; caps +2 pts/quarter, +6 pts/12mo — AMH_RULES §3.5).

How to go deeper

Ask an agent with the railway-internal MCP (the gauge_* / ahrefs_* / posthog_* tools) or the amh-growth skill for observed-anchor pricing, live SERP inspection, topic curation, and citation checks.

Ahrefs cost: 1174 API units · How AMH is calculated