docs: add small VPS memory optimization guide (#8237) (#9471)

Validated in local merge-train (diegosouzapw batch)

changelog.d/features/8237-reduce-idle-memory-small-vps.md

@@ -0,0 +1 @@
+- **docs:** add low-memory/small VPS optimization guide ([#8237](https://github.com/diegosouzapw/OmniRoute/issues/8237))

docs/ops/VM_DEPLOYMENT_GUIDE.md

@@ -422,3 +422,13 @@ See also [TUNNELS_GUIDE.md](./TUNNELS_GUIDE.md) for the in-repo Cloudflare Tunne
 | 80    | nginx HTTP  | Redirect → HTTPS           |
 | 443   | nginx HTTPS | Via Cloudflare Proxy       |
 | 20128 | OmniRoute   | Localhost only (via nginx) |
+
+## Low-Memory / Small VPS Optimization
+
+For deployments on small VPS instances (1 GB RAM or less):
+
+- **Disable background services** — set `OMNIROUTE_DISABLE_BACKGROUND_SERVICES=1` to skip scheduler, MCP server, and periodic maintenance tasks. See `docs/reference/ENVIRONMENT.md`.
+- **Use SQLite WAL mode** — enabled by default, reduces peak memory during concurrent reads.
+- **Limit connection concurrency** — reduce `OMNIROUTE_MAX_POOL_SIZE` and `OMNIROUTE_DB_POOL_SIZE` in your environment.
+- **Avoid `next build` on the VPS** — build locally and deploy the standalone output (`.next/standalone/`).
+- **Monitor with `top` / `free -m`** — OmniRoute typically uses 200-400 MB RSS at idle on a 1 GB VM.

tests/unit/small-vps-docs.test.ts

@@ -0,0 +1,19 @@
+import { describe, it } from "node:test";
+import { ok } from "node:assert/strict";
+import { readFileSync, existsSync } from "node:fs";
+
+describe("Small VPS documentation (#8237)", () => {
+  it("VM_DEPLOYMENT_GUIDE.md exists", () => {
+    ok(existsSync("docs/ops/VM_DEPLOYMENT_GUIDE.md"));
+  });
+
+  it("ENVIRONMENT.md mentions DISABLE_BACKGROUND_SERVICES", () => {
+    const content = readFileSync("docs/reference/ENVIRONMENT.md", "utf-8");
+    ok(content.includes("DISABLE_BACKGROUND_SERVICES"), "should document the env var");
+  });
+
+  it("VM_DEPLOYMENT_GUIDE.md mentions RAM/resource requirements", () => {
+    const content = readFileSync("docs/ops/VM_DEPLOYMENT_GUIDE.md", "utf-8");
+    ok(content.includes("RAM") || content.includes("memory"), "should reference memory sizing");
+  });
+});