Emergency Incident Response
Cache down, evictions running away, or a database melting from a miss storm. A senior engineer joins a live bridge within 15 minutes with access to diagnose — not a ticket acknowledgement.
Memcached Support
Last reviewed by Scott Sternloff
AceMQ supports Memcached in production — slab calcification, eviction storms while memory looks free, maxconns exhaustion, and the cache-miss stampede that follows a node loss. Every ticket reaches a named senior engineer who already knows your cache topology and your client library.
Planning a build, upgrade or migration instead? See AceMQ Memcached consulting and services.
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Incident Triage
These are real symptoms from real Memcached production environments — and the first thing our engineers check when one comes in.
| Symptom you're seeing | What we check first | Typical resolution |
|---|---|---|
| Evictions climbing fast while the cache still reports free memory | Per-slab-class stats from `stats slabs` and `stats items`. This is nearly always slab calcification — memory already assigned to one chunk size cannot be handed to another after your item size distribution shifts, so one class evicts while others sit half empty. | 1–3 hours |
| Database CPU spikes to 100% seconds after a Memcached node drops | Whether your client is using consistent hashing (ketama) or modulo hashing. Modulo remaps nearly every key on a ring change and sends the entire keyspace to the database at once. We check client config first, then add request coalescing on the hot keys. | 1–2 hours |
| Clients getting connection refused or timeouts under load | `stats` listen_disabled_num against the maxconns setting (-c, default 1024). Once that counter is non-zero the daemon is refusing connections outright — usually a client pool that opens a connection per thread rather than pooling. | Under 1 hour |
| Some SET operations silently fail and the key never appears | Item size against the 1MB slab limit (-I). Values crossing that boundary are rejected with SERVER_ERROR object too large for cache, which many client libraries swallow. We measure the serialized size distribution before touching the limit. | Under 1 hour |
| Hit ratio collapsed overnight with no deploy and no traffic change | Uptime and total_items on each node. An ElastiCache Memcached node replacement or a daemon restart wipes the cache completely — there is no persistence — so we correlate the drop against node uptime and maintenance windows first. | Under 1 hour |
| get latency is fine at p50 but terrible at p99 | Whether the LRU crawler and slab automover are running, plus network-level factors — Nagle interaction with small gets, and whether the client batches with multiget or issues serial round trips per key. | 2–4 hours |
| Cache and database disagree — users see stale data after a write | The invalidation path. Cache-aside with delete-after-commit races against a concurrent read that repopulates the old value. We map the write path and usually move to CAS-guarded updates or short-TTL leases. | 2–4 hours |
| Memory usage keeps growing and never plateaus | TTL policy across key namespaces. Memcached expires lazily, so keys written without a TTL occupy slabs until evicted by LRU pressure. We audit which code paths write with TTL 0 and cap them. | Same day |
Resolution times reflect typical Memcached engagements under an active AceMQ support contract. Every P1 closes with a written root-cause analysis.
What's Included
No add-on pricing for incidents. No per-ticket charges. One contract covers the whole surface.
Cache down, evictions running away, or a database melting from a miss storm. A senior engineer joins a live bridge within 15 minutes with access to diagnose — not a ticket acknowledgement.
Every P1 closes with a written RCA: what failed, why, the fix applied, and the specific configuration or client-side change that prevents recurrence. Standard, not on request.
Slab growth factor, chunk size boundaries, LRU crawler and slab automover settings tuned against your real item size distribution — so allocated memory tracks what you actually cache.
Consistent hashing configuration, connection pooling, multiget batching, and timeout and retry policy across your client libraries. Most Memcached incidents are client-side and get fixed there.
Binding, SASL authentication, UDP disablement, and network policy. Memcached has no authentication by default and has been abused for reflection amplification — we verify the exposure surface.
Quarterly review of hit ratio trends, eviction rates, working set growth, and node sizing so you scale ahead of the miss storm rather than during it.
Why AceMQ
The same senior engineers stay on your account. They know your key namespaces, item size profile, and client stack — so a P1 call starts with diagnosis, not twenty minutes of you describing your cache tier.
You reach a senior engineer directly by phone, email, or Slack. No help desk collecting information to pass along, and no escalation approval standing between you and someone who can actually fix it.
A Memcached incident usually surfaces as a database incident. We work both sides — cache behaviour and the query load it was shielding — because fixing only one of them leaves the outage half solved.
Engineers across 26+ countries and every time zone. Your 3am incident is someone's mid-afternoon — no overnight skeleton crew, no waiting for a region to wake up.
Quarterly health checks plus shared intelligence across our support base. When a version-specific bug or client library regression surfaces on one cluster, every affected customer hears about it early.
Memcached is the right answer for a pure LRU cache and the wrong one for anything needing persistence, data structures, or replication. We will tell you which side of that line you are on before you spend a quarter migrating.
Cloud, Kubernetes, bare metal, hybrid, and air-gapped — including environments where you can't give us outbound network access.
Escalation Path
Every tier reaches a senior Memcached engineer. There is no tier-1 triage layer to get through.
P1 escalation path
A replay of one P1, from the first page to the written root-cause analysis
15-minute P1 response, 24/7.
A response time, not a resolution time.
P1 opened, on-call engineer paged
Phone, email or Slack reaches the on-call senior engineer directly, whether the incident is in RabbitMQ, Kafka, Redis, PostgreSQL or Kubernetes. No web form, no tier-1 queue.
Senior engineer on your bridge
A senior engineer who already knows your environment joins a live bridge, so nobody has to re-explain your topology.
Specialists across the stack join
When an incident crosses components, the engineers who know each one join. For RabbitMQ, the path runs to the core team.
Written root-cause analysis
Root cause, the fix applied and the prevention steps, delivered after every P1.
Pricing
AceMQ Memcached support contracts typically run $24,000–72,000 a year, depending on SLA level, scope (number of clusters or nodes, and environments) and deployment (self-managed, cloud-managed or Kubernetes).
| What moves the price | How it changes the contract |
|---|---|
| SLA level | Business-hours cover costs less than 24/7 cover with a 15-minute emergency response. |
| Scope | More clusters or nodes, and more environments, make a larger contract. |
| Deployment | Self-managed, cloud-managed and Kubernetes estates need different amounts of hands-on work. |
Covering several technologies under one contract, for example RabbitMQ, Kafka and Redis, earns an aggressive discount.
Support In Practice
Memcached support and consulting work from AceMQ. Each card links to the full write-up: the cache tier, what AceMQ diagnosed or changed, and the result.
Digital Commerce Platform
Emergency remediation of a Memcached tier evicting hot keys while reporting free memory, traced to slab class allocation.
Digital Media Platform
Ongoing support for a Memcached tier prone to thundering-herd database load after node changes and cache expiry cliffs.
B2B SaaS Platform Provider
Assessment of Memcached sizing, key distribution, and hit rate to determine whether adding capacity would actually help.
Global Payments Processor
Consulting engagement to design multi-region Memcached topology, key namespacing, and invalidation strategy for a latency-sensitive platform.
Support options
AceMQ offers Memcached support in four tiers, each handing more of the day-to-day work to AceMQ: 24/7 support and incident management for tiers your team runs, proactive monitoring that catches slab imbalance and hit-ratio drift first, managed Memcached on your own infrastructure, and fully managed Memcached on AceMQ infrastructure. Self-managed nodes and Amazon ElastiCache are covered in all four.
You run it, we back you up
Best for: Teams that run Memcached or ElastiCache themselves and need senior cover when the cache goes cold at 3am.
You run it, we watch it with you
Best for: Estates where a cold cache or an exposed port is not an acceptable surprise.
We run it in your cloud or data centre
Best for: Regulated teams that must keep the cache tier inside their own boundary without staffing it.
We host it and run it, as a service
Best for: Teams that want a cache tier that stays up without owning its operations.
| Who does what | Tier 1 24/7 support | Tier 2 Proactive monitoring | Tier 3 Managed, your infrastructure | Tier 4 Fully managed by AceMQ |
|---|---|---|---|---|
| Who runs Memcached day to day? | Your team | Your team, with AceMQ reviews | AceMQ | AceMQ |
| Where does it run? | Your infrastructure | Your infrastructure | Your cloud account or data centre | AceMQ infrastructure |
| 24/7 incident response | 15-minute P1 response | 15-minute P1 response | 15-minute P1 response | 15-minute P1 response |
| Health checks and CVE alerts | On request | Scheduled | Included | Included |
| Patching and upgrades | Your team, AceMQ advises | Planned with AceMQ | Done by AceMQ | Done by AceMQ |
| Monitoring and on-call | Your team | Your team | AceMQ | AceMQ |
| Data, keys and accounts | Yours | Yours | Yours | Your data, hosted by AceMQ |
Every Tier can start as an ad hoc engagement or an annual partnership, and you can move up or down a Tier as your team changes.
One partner for Memcached
Support is one part of what AceMQ does for Memcached. The same engineers deliver consulting, health checks, migrations and end-of-life cover, and support the systems that usually run next to it.
Our Memcached support covers 24/7 emergency incident response with a 15-minute SLA, root cause analysis on every P1, slab and memory tuning, client and hashing review, security exposure review, and quarterly capacity checks. Every ticket is handled by a named senior engineer assigned to your account — there is no tier-1 triage layer and no per-incident charge.
Yes. We support ElastiCache for Memcached alongside self-managed deployments. ElastiCache removes some operational surface but not the ones that cause incidents: node replacement wipes the cache with no persistence, slab calcification still happens, connection limits still bite, and client-side hashing configuration is still yours to get right. That is where most of our diagnostic time goes.
Almost always slab calcification. Memcached carves memory into slab classes by chunk size, and once a page is assigned to a class it stays there. If your item size distribution shifts — a new field on a cached object, a serialization change — the class holding those items runs out of pages and evicts, while other classes hold memory it cannot borrow. The fix is a combination of slab automover, growth factor tuning, and sometimes a controlled restart with a corrected layout.
P1 emergencies — cache down, eviction storm, database saturating from cache misses — get a 15-minute first response with a senior engineer joining a live bridge. P2 critical issues are 1 hour, P3 high-priority 4 hours, and P4 standard questions next business day. These are contractual, not best-effort targets.
Both, and the client side is usually where the fix lands. Consistent hashing configuration, connection pooling, multiget batching, timeout and retry policy, and serialization size are all client concerns, and all common root causes. We review the client library configuration as part of every engagement rather than treating it as out of scope.
Memcached is the better fit when you need a simple, multi-threaded, LRU-evicting cache and nothing else — it is very hard to beat on raw throughput per core for that job. Redis is the answer when you need persistence, replication, data structures, pub/sub, or Lua-side atomicity. We assess your actual access patterns and say which one fits, including telling you to stay where you are when a migration would not pay for itself.
Yes. AceMQ works on Memcached in two ways: ad hoc engagements for a defined piece of work, such as a health check, an upgrade or an incident, or an annual partner engagement that covers 24/7 support, proactive reviews and named engineers. Many teams start ad hoc and move to an annual partnership once the first engagement is done.
Every AceMQ proposal is tailored to your requirements: your Memcached environment, the SLA you need, the hours of cover and the scope of work. Most contracts run $24,000–72,000 a year, depending on the SLA, the scope and how Memcached is deployed, with aggressive discounts when several technologies share one contract. Request a quote and AceMQ replies within 1 hour.
Let's talk
Reactive cover, proactive reviews, or AceMQ running Memcached for you on your infrastructure or ours. A senior engineer scopes it with you, and quote requests are answered within 1 hour.
Production incident right now?Email a Memcached Architect
Send us a message and we'll follow up within 1 hour — or book a free 30-min consultation directly.
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