Spedo / Practical guides

Single-node cache / practical evaluation

Evaluate a single-node cache before adoption

Define a bounded workload, check command behavior, test failure handling and keep recovery evidence separate from performance claims.

Updated October 27, 2026 · Preview scope · disposable data · documented RESP commands

A fast response in a demo is a useful beginning. Adoption needs evidence that matches the application: correct responses, explicit failure behavior, a memory budget and an understood recovery boundary. Spedo is a single-node in-memory engine in preview. Evaluate a rebuildable cache or derived state with a separate source of truth.

Write the workload boundary first

Record the commands, payload sizes, TTL distribution, client version, peak concurrency and expected memory footprint. State which system owns the authoritative data. Exclude irreplaceable primary data, multi-node failover assumptions and an implied Redis Cluster replacement from this first evaluation.

Define success before measuring: for example, exact response equality, an acceptable cache-miss fallback, a memory ceiling and a latency budget on your own infrastructure. A read-only microbenchmark and a mixed application workload answer different questions.

Prove the small behavior

Run the JSON response and TTL walkthrough. Add the application’s actual commands and compare returned values, missing keys, errors and expiration behavior. For structured RESP features, test the required subset rather than inferring all behavior from successful GET and SET commands.

Use disposable synthetic records. Keep a concise transcript with the build identity and expected versus actual output so another developer can repeat the check.

Exercise a cache miss and an unavailable cache

Let a known key expire and check that the application fetches the correct authoritative value. In an isolated test deployment, stop the cache and confirm that request handling follows the intended fallback. Decide whether callers receive a controlled error, stale data or an upstream fetch. Observe whether repeated misses overload that upstream service.

Keep these tests separate from production traffic. Do not change shared-instance memory policy or stop a production service to reproduce a tutorial.

Validate recovery as a separate workload

If local recovery is required, read the snapshot and WAL operator guide and choose the exact qualified profile. Use a disposable persistent volume, record acknowledged writes, perform the documented checkpoint operation, restart the same isolated instance and compare recovered values. A process restart, a crash and a disk failure require distinct checks.

Retain the command transcript, configuration and recovery result. Repeat failure cases relevant to the deployment, such as a full disk or damaged copied artifact, in an isolated environment. A successful local recovery test is not evidence of replication, quorum durability or automatic failover.

Measure the trade-off you actually care about

Record latency distributions as well as throughput, and keep payload sizes, concurrency, client overhead and persistence settings visible. Use the benchmark methodology and linked raw results to distinguish server, SDK and local-cache paths. A local cache read is not a server round trip, and a write-behind enqueue is not a durable server acknowledgment.

Make the adoption decision explicit

Keep the passing checks, failures and unanswered questions together. Start with a bounded rollout only when the application’s fallback and operational ownership are clear. The design-partner evaluation is available for a scoped preview; it is not a production certification or an availability contract.