diff --git a/.env.example b/.env.example
index 31f1caf..e6ffdd6 100644
--- a/.env.example
+++ b/.env.example
@@ -21,3 +21,16 @@ INFLUXDB_TOKEN=mytoken123456789
 INFLUXDB_ORG=mikrotik-manager
 INFLUXDB_BUCKET=metrics
 INFLUXDB_ADMIN_PASSWORD=admin_password_123
+
+# ─── Poller tuning (see GET /api/system/poller) ──────────────────────────────
+# Raise concurrency if `headroom` in the poller health endpoint drops near 1.0 —
+# below that the queue grows every cycle and devices go stale.
+# POLLER_CONCURRENCY=12
+# POLLER_JOB_TIMEOUT_MS=45000
+# POLLER_INTERVAL_MS=30000
+# POLLER_JOB_RETENTION_SEC=3600
+# POLLER_JOB_RETENTION_COUNT=5000
+
+# Redis memory ceiling. Only TTL-bearing keys are evicted (volatile-lru), so
+# queued jobs are never discarded; the cap exists to protect the host.
+# REDIS_MAXMEMORY=512mb
diff --git a/README.md b/README.md
index f131f26..3da4552 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@
 </p>
 
 <p align="center">
-  <img src="https://img.shields.io/badge/version-0.23.17_Beta-blue" alt="Version" />
+  <img src="https://img.shields.io/badge/version-0.23.18_Beta-blue" alt="Version" />
   <img src="https://img.shields.io/badge/license-AGPLv3-blue" alt="License" />
   <img src="https://img.shields.io/badge/docker-compose-2496ED?logo=docker&logoColor=white" alt="Docker" />
   <img src="https://img.shields.io/badge/TypeScript-5.3-3178C6?logo=typescript&logoColor=white" alt="TypeScript" />
diff --git a/backend/package.json b/backend/package.json
index fcb9841..d2636fa 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -1,6 +1,6 @@
 {
   "name": "mikrotik-manager-backend",
-  "version": "0.23.17-beta",
+  "version": "0.23.18-beta",
   "description": "Mikrotik Network Management Platform - Backend API",
   "main": "dist/index.js",
   "scripts": {
diff --git a/backend/src/services/PollerService.ts b/backend/src/services/PollerService.ts
index e36f86f..76ac9ba 100644
--- a/backend/src/services/PollerService.ts
+++ b/backend/src/services/PollerService.ts
@@ -159,12 +159,19 @@ export class PollerService {
         attempts: 3,
         backoff: { type: 'exponential', delay: 5000 },
       });
+    // Periodic polls are not retried in-job: the schedule is the retry. A device
+    // that just failed to answer is unlikely to answer a second later, and each
+    // extra attempt occupies a worker for up to the job timeout. On a fleet with
+    // several devices down that doubles the capacity they waste, which is exactly
+    // the capacity the rest of the fleet is short of (#114). Historically this
+    // also doubled the recorded failure count: 231k failed jobs on a four-device
+    // fleet turned out to be ~1,000 hours of genuine downtime, counted twice.
     } else if (type === 'fast') {
-      await this.fastQueue.add('device-fast-poll', jobData, { attempts: 2 });
+      await this.fastQueue.add('device-fast-poll', jobData, { attempts: 1 });
     } else if (type === 'slow') {
-      await this.slowQueue.add('device-slow-poll', jobData, { attempts: 2 });
+      await this.slowQueue.add('device-slow-poll', jobData, { attempts: 1 });
     } else if (type === 'logs') {
-      await this.logsQueue.add('device-logs-poll', jobData, { attempts: 2 });
+      await this.logsQueue.add('device-logs-poll', jobData, { attempts: 1 });
     } else if (type === 'macscan') {
       await this.fastQueue.add('device-macscan', jobData, { attempts: 1 });
     } else if (type === 'spectral') {
diff --git a/docker-compose.yml b/docker-compose.yml
index 6fe9683..c48f867 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -85,7 +85,16 @@ services:
 
   redis:
     image: redis:7-alpine
-    command: redis-server --appendonly yes
+    # A memory ceiling so a runaway producer can never take the host down. The
+    # eviction policy is deliberately volatile-lru rather than allkeys-*: BullMQ
+    # job data carries no TTL and must never be evicted (that would silently
+    # destroy queued work), while the poller's caches and in-flight claims all
+    # set one and are safe to drop. If pressure ever exhausts the volatile keys
+    # Redis refuses writes instead of evicting queue state — loud, and survivable.
+    command: >
+      redis-server --appendonly yes
+      --maxmemory ${REDIS_MAXMEMORY:-512mb}
+      --maxmemory-policy volatile-lru
     volumes:
       - redis_data:/data
     restart: unless-stopped
diff --git a/frontend/package.json b/frontend/package.json
index 2d064da..822ff00 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,6 +1,6 @@
 {
   "name": "mikrotik-manager-frontend",
-  "version": "0.23.17-beta",
+  "version": "0.23.18-beta",
   "private": true,
   "type": "module",
   "scripts": {
diff --git a/frontend/src/version.ts b/frontend/src/version.ts
index 2252b75..a457959 100644
--- a/frontend/src/version.ts
+++ b/frontend/src/version.ts
@@ -1 +1 @@
-export const APP_VERSION = 'v0.23.17 Beta';
+export const APP_VERSION = 'v0.23.18 Beta';