Redis RDB vs AOF Is Really an RPO Decision
RDB and AOF are not just file formats. They encode how much acknowledged state you are willing to lose, how much persistence overhead you accept, and how recovery should work.
redis
Waiting Sessions Tell Me More Than CPU During Database Contention
A production-engineering deep dive into waiting sessions tell me more than cpu during database contention, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
Redis 8.6 Streams Finally Address the Producer Retry Ambiguity Directly
A producer can time out after XADD without knowing whether Redis accepted the entry. Redis 8.6 adds stream idempotency so retries can be recognized without creating duplicate entries.
Redis Evictions Mean Memory Policy Is Affecting Data
Redis can remain responsive while silently evicting keys because the configured memory limit has been reached.
Redis Eviction Means Policy Is Already Affecting Data
A production-engineering deep dive into redis eviction means policy is already affecting data, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
The Redis Streams Pending Entries List Is Your Work-in-Progress Ledger
Consumer groups do not make a stream entry disappear when it is delivered. Until XACK succeeds, Redis tracks it as pending, which is what makes crashed-consumer recovery possible.
A Single Redis Hot Key Can Defeat the Point of a Cluster
Redis Cluster spreads hash slots across shards, not one key across shards. A single extremely popular key can saturate the shard that owns it while the rest of the cluster is mostly idle.
Redis Failure Is Not the Same as Web-App Failure
Why dependency failures should be diagnosed as graph problems instead of pod problems.
One PostgreSQL Deadlock Is Worth Recording
A production-engineering deep dive into one postgresql deadlock is worth recording, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
Redis Fragmentation Can Look Like a Memory Leak
A production-engineering deep dive into redis fragmentation can look like a memory leak, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
Redis Replication Can Lose Acknowledged Writes During Failover
Redis replication is asynchronous by default. WAIT reduces the risk window, but replica acknowledgements do not turn Sentinel or Cluster failover into a strongly consistent system.
PostgreSQL Connection Utilization Needs a Denominator
A production-engineering deep dive into postgresql connection utilization needs a denominator, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
A Single Redis Replica Is a Design Choice, Not a Default Truth
How I interpret the current one-replica values and what changes when availability requirements grow.
Redis Functions Are Atomic — Which Is Exactly Why Slow Ones Hurt
Lua scripts and Redis Functions avoid races and network round trips by executing atomically on the server. The same property means long-running server-side code blocks unrelated work.
Control Plane, Data Plane, and Queue Dependencies in Voiceware
A mental model for separating deployment control from application traffic and background work.
Redis in Voiceware: Small Manifest, Central Dependency
Why an internal Redis service deserves explicit operational attention.
Authelia Sessions Needed Durable State, Not Just Longer Cookies
A longer browser cookie does not help if the server forgets the session behind it.
Redis maxmemory Is Not a Capacity Setting — It Is a Data-Loss Policy
When Redis reaches maxmemory, the eviction policy decides which data may disappear or whether new writes should fail. That makes memory configuration part of application correctness.
Using Redis Beside Kamailio Without Making Redis the Whole Architecture
Redis was useful for fast shared state in a SIP lab, but the important decision was which state belonged there and how the proxy behaved when it disappeared.
Redis used_memory Can Look Fine While RSS Keeps Growing
Allocator fragmentation, active pages, copy-on-write during forks, and persistence work can make process RSS diverge from the logical size of the Redis dataset.
Buffer Hits, Disk Reads and the Shape of PostgreSQL Cache Pressure
A production-engineering deep dive into buffer hits, disk reads and the shape of postgresql cache pressure, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
Redis Cluster Hash Tags Are a Data-Model Decision, Not a Syntax Trick
Hash tags let related keys share one slot so multi-key commands and scripts can remain atomic. Overuse them and you can create hot slots that undo the cluster's distribution.
A Successful TCP Connection Does Not Mean the Database Is Healthy
A production-engineering deep dive into a successful tcp connection does not mean the database is healthy, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
Temporary I/O Is a Query-Behavior Signal
A production-engineering deep dive into temporary i/o is a query-behavior signal, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
Redis and PostgreSQL Have Different Jobs in the Authelia Stack
Persistent SSO works better when ephemeral session state and durable identity-provider state are not confused.
ClusterIP and Service Discovery for Redis
How an internal service name is preferable to hard-coding pod identity.
Redis Memory Needs Role Context
A Redis instance serving disposable cache and one serving authentication sessions can show the same memory growth with very different operational risk.
A Redis Cache Miss Can Become a Database Outage
When a popular key expires, many callers can observe the same miss and rebuild the value simultaneously. Stampede protection is admission control for the source of truth.
Four Database Engines on One Small Server: Observability Without Exporter Sprawl
A production-engineering deep dive into four database engines on one small server: observability without exporter sprawl, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.
MySQL Slow Queries Belong in Infrastructure Monitoring
A production-engineering deep dive into mysql slow queries belong in infrastructure monitoring, grounded in the 2014 Mac mini hserver observability stack and its accepted runtime evidence.