Memcached

A fast, ephemeral in-memory cache for keys you can regenerate from your source of truth.

Creating a Memcached instance

From the dashboard, click New service, then Database, then Memcached. StackBlaze provisions the instance and gives it a stable internal hostname.

Attach Memcached to your service from the Environment tab. StackBlaze injects MEMCACHED_SERVERS automatically, so your app reads the server address from the environment rather than hardcoding it.

Memcached is a simple, very fast in-memory key-value cache for ephemeral data. It has no persistence: keys live only in memory and are meant to be regenerated on demand. Use it to take load off a slower backing store (a database or an external API) by caching the results of expensive lookups.

Connecting

Memcached speaks its own lightweight text and binary protocol on port 11211. Most clients accept a list of server addresses, which is exactly what MEMCACHED_SERVERS provides. The internal server address takes the form below.

[service-name].internal:11211

Connect from within the cluster using this address. There is no connection URL scheme and, by design, no query language: you set, get, and delete keys.

Deployment model

Memcached runs as a Standard single instance. It is an ephemeral cache that holds no durable data and does not replicate, so there is no high-availability mode. If the node is lost, the keys it held are simply re-fetched from your source of truth (your database) on the next request and written back into the cache.

For more cache capacity, you can add nodes and shard keys across them client-side. Most Memcached clients support a server list and hash each key to a server, so adding a node spreads keys without any coordination between the nodes themselves.

Connecting from Python

The pymemcache client reads the server address straight from MEMCACHED_SERVERS, then sets and gets keys.

import os
from pymemcache.client.base import Client

# e.g. "[service-name].internal:11211"
host, port = os.environ["MEMCACHED_SERVERS"].split(":")
client = Client((host, int(port)))

client.set("user:42", "Ada Lovelace", expire=3600)  # TTL: 1 hour
value = client.get("user:42")
print(value)  # b"Ada Lovelace" (or None if the key was evicted)

When to use Memcached vs Redis

Use Memcached when you want the simplest possible pure in-memory cache: keys, values, and TTLs, nothing more. Reach for Redis (Valkey) when you need persistence, richer data structures (lists, sets, sorted sets, hashes), pub/sub messaging, or replication. See /docs/databases/redis for the Redis offering.