Role in the platform
Redis serves multiple purposes:
By convention, each purpose uses a distinct logical Redis
db number (or a dedicated cluster).
Redis is no longer used as a vector database since the v27 platform. The Knowledges vector store now lives on Elasticsearch or OpenSearch.
RedisJSON and RediSearch modules are not required.Version compatibility
- Minimum: Redis 6.2+.
- Redis 7.x supported and recommended.
- Standard Redis is sufficient — no special modules required.
Recommended deployment
Topology: Multi-AZ for HA. Minimum: 3 GB RAM, 2 vCPU per instance.
We recommand 2 separate instances : one dedicated to the event broker, and another for everything else (cache/sessions).
Helm Configuration
Helm keys that point to Redis:url (e.g. redis://user:password@host:6379/3) and optionally password.
By convention we allocate db numbers per service (e.g. 0 = broker, 2 = runtime cache, 3 = sessions, 4 = searchengines). Adjust when sharing a cluster.
See Helm install for the full install context.
Redis configuration
maxmemory-policy per instance
Despite the “cache” naming, the runtime contexts cache and the crawler search engine state are not LRU caches — both hold operational state that must not disappear mid-operation. Set the eviction policy per Redis instance:
If you co-locate several of these on a single Redis instance (via distinct
db numbers), the strictest policy wins — noeviction — so plan capacity accordingly. The recommended layout is 2 separate instances for broker & everything else.
Backup & restore
RDB snapshots
AOF (append-only file)
For lower RPO, enable AOF in addition to RDB:Managed services
- ElastiCache: enable automatic daily snapshots, retain ≥ 7 days.
- Azure Managed Redis: enable RDB persistence to a storage account.
- Memorystore: enable scheduled exports to GCS.
What’s safe to lose
- Broker (Redis Streams): only contains in-flight events with a
maxLencap. Losing it triggers re-processing at worst. - **Runtime **: active users encounter issues until runtime restart
- Contexts cache is rebuildable on prismeai-runtime restart
- Scheduled automations would also be lost until their next save (or a simple platform pull for Prisme.ai AI products)
- Sessions store: users won’t be disconnected as we use stateless JWK, no impact.
Updates
- Redis is forward-compatible across minor versions; the platform requires 6.2+.
- Cluster-mode support has been available in Prisme.ai since v3.2.
- For major Redis upgrades (e.g. 6 → 7): plan a maintenance window and fail over the replica.
Scaling
- Vertical: increase memory and IOPS — Redis is memory-bound.
- Cluster mode: shard the keyspace for horizontal scale. Useful when broker streams grow beyond a single node’s RAM.
- Replicas: add read replicas if you offload read-heavy queries.
- Monitoring: track memory usage, connected clients, command latency, evicted keys.