Redis

Yes, Redis on Kubernetes supports automatic failover for high availability.

Redis can be used as a primary database in production for specific use cases requiring high availability and persistence.

Redis can be used alongside disk-based databases in production environments.

Yes, Redis allows disabling persistence entirely for scenarios where data durability is not required.

Yes, Redis Enterprise Cloud supports HIPAA and SOC 2 compliance.

Redis Pub/Sub operates independently of the Redis key space.

No, Redis continues processing all commands in a transaction even if one fails.

Redis does not fully support ACID transactions as it lacks rollback functionality.

Redis Pub/Sub guarantees that subscribers receive messages in the exact order they are published.

Messages in Redis Streams are stored in a radix tree structure for efficient memory usage.

To import a dataset from a Redis Open Source server, select Import in the Redis Cloud console.

Data can be ingested and synchronized to Redis using Redis Data Integration features.

Data persistence can be set to AOF using the admin UI or REST API requests.

Download the syncer certificate, edit TLS settings in the source database's Security tab, and save the configuration.

Run CONFIG SET latency-monitor-threshold <milliseconds> to enable latency monitoring.

Redis can be deployed on Kubernetes by following the Kubernetes deployment quick start guide.

Redis can be installed using the OS package manager or a script for the latest version.

Change high availability settings in Redis Cloud through the Durability settings panel in the subscription details page.

You can change the eviction policy in Redis Cloud by editing the database details through the interface.

Monitoring involves collecting logs and connecting to Prometheus for metrics.

1 million keys with 5 fields each use about 160 megabytes of memory on a 64-bit Redis instance.

Set 'port 0' to disable non-TLS and 'tls-port 6379' to accept TLS connections on port 6379.

Use the command: redis-cli -h <endpoint> -p <port> --tls --cacert redis_ca.pem --cert redis_user.crt --key redis_user_private.key.

To enable TLS encryption in Redis Cloud, select your database, click Edit, and toggle the TLS option in the Security section.

Data can be migrated from Memcached to Redis using the Redis input and output CLI tool.

Redis ensures atomicity by blocking all server activities during the script's execution.

Redis Streams and Apache Kafka are both used for streaming data but differ in architecture and use cases.

Cluster recovery is initiated by editing the REC resource with a specific command.

In Redis, longer keys and values show asymptotically linear memory usage.

Redis allocates memory for user keys up to the limit set by the maxmemory configuration setting.

Redis Cloud facilitates GDPR compliance by ensuring data residency.

Redis Cloud supports multi-factor authentication and SAML SSO.

Redis Cluster broadcasts published messages to all nodes, ensuring delivery to subscribed clients.

Redis replays all write commands from the AOF file to reconstruct the dataset.

Redis uses redis.pcall() to handle errors in Lua scripts.

Redis sends all write operations performed by a script to replicas for consistency.

Redis on Kubernetes achieves high availability by deploying instances across multiple zones and enabling automatic failover.

Redis Sentinel reconfigures replicas to replicate from the correct master once they become reachable again.

Redis Sentinel detects failures through a quorum of Sentinel processes agreeing on a master being unavailable.

Redis Streams manages message retention using the XTRIM command to limit the number of stored messages.

Redis Streams supports multiple consumers through consumer groups, allowing collaborative processing of messages.

Sharded Pub/Sub restricts message propagation to the responsible shard.

In Redis 6.2, INFO commandstats aggregates statistics; Redis 7.0 reports them separately for each sub-command.

A Redis Transaction is started by issuing the MULTI command.

Use redis-cli with the --intrinsic-latency option to measure intrinsic latency.

A minimum of three nodes is required for a Redis Enterprise Software production cluster.

Use the LATENCY command and LATENCY DOCTOR command to monitor latency spikes with Redis CLI.

Set up high availability for Redis on AWS by deploying across multiple Availability Zones and enabling replication settings.

No, Redis Cluster and Redis Sentinel are different systems with distinct functionalities.

RedisJSON is a separate module for Redis.

Redis Cloud supports role-based access control and permissions management.

TLS configuration options include protocol versions, ciphers, and cipher suites in the redis.conf file.

Redis Streams can be used for stronger delivery guarantees than Pub/Sub.

Redis is commonly used for document databases, feature storage, and gaming leaderboards in production.

Redis supports three appendfsync options: always, every second, and no fsync.

Redis Streams provide at-least-once delivery guarantees, while Pub/Sub uses at-most-once semantics.

Redis Enterprise supports several eviction policies including noeviction, allkeys-lru, and volatile-lfu.

1) Firewall Redis ports, 2) configure the 'bind' directive, 3) enable 'requirepass', 4) use SSL tunneling software.

Key features of Redis Streams include consumer groups, automatic ordering, and retention management.

Key considerations include CPU resources, RAM for datasets, and network throughput.

Redis 8.0 is available under RSALv2, SSPLv1, or AGPLv3 licenses.

Redis Cluster consists of multiple Redis nodes that manage data sharding and replication.

Prerequisites include a running Kubernetes cluster, at least three worker nodes, and access to container registries.

Create a Redis Cloud Pro database and an AWS Transit Gateway in the same region as your database.

Data import into a Redis Cloud database requires an accessible source URI and a Redis backup file format.

Best practices include firewalling ports, using TLS, setting strong passwords, and limiting access to trusted clients.

Go to the database's Security tab, select Edit, check the TLS box, and save the configuration.

Sign up for Redis Cloud, create a database, enable TLS, and store credentials in AWS Secrets Manager.

Redis 7.0 introduced changes that may break existing functionality, including modifications to error responses and command behaviors.

RedisJSON uses Cargo, the Rust language build system.

The LATENCY DOCTOR command analyzes latency issues in Redis.

The MEMORY DOCTOR command analyzes memory usage and provides insights.

Redis 7.0 made changes to command behaviors, including how certain commands are treated in scripts.

The LATENCY GRAPH command shows a graphical representation of latency events.

Use the command: './src/redis-server --tls-port 6379 --port 0' with certificate options.

The MIGRATE command is used to migrate multiple keys in Redis.

The LATENCY RESET command clears all collected latency data in Redis.

PFCOUNT and PUBLISH commands are blocked in read-only Lua scripts.

The central commands for Redis Transactions are MULTI, EXEC, DISCARD, and WATCH.

The Redis JSON category contains all commands related to JSON data manipulation.

Commands like XADD, XREAD, and XACK are used to interact with Redis Streams.

The commands SUBSCRIBE, UNSUBSCRIBE, and PUBLISH implement Pub/Sub in Redis.

Users should review breaking changes and update applications accordingly before upgrading to Redis 7.0.

Redis Cloud supports compliance certifications including HIPAA and SOC 2.

The maxmemory-policy configuration directive selects the eviction policy in Redis.

Large keys in Redis are defined as keys that are hundreds of kilobytes or larger.

Every key in Redis requires memory for the key name and some per-key overhead.

Redis Cloud recommends employing at least one network security option, such as IP Restrictions or VPCs.

Redis Cluster automatically shards data across multiple Redis nodes for horizontal scaling.

redis_used_memory measures the total memory used by the shard in bytes.

Atomicity guarantees that multiple keys can be updated simultaneously without partial updates.

The Redis eviction policy controls the automatic removal of keys when memory limits are exceeded.

PUBSUB NUMSUB returns subscriber counts from the specific node's context.

Redis Cloud provides encryption at rest and in transit.

An extra guarantee of optimistic locking was added starting with Redis version 2.2.

Redis transactions guarantee atomic execution of all commands in a transaction block.

During a failover, Redis Sentinel promotes a suitable replica to master after detecting a master failure.

Redis converts oversized specially encoded values into normal encoding automatically.

If a subscriber cannot handle a message, it is lost permanently.

The transaction aborts with a WatchError exception if a watched key changes.

If the license field is not provided, a trial license is set by default.

Imported data overwrites any existing data in the target Redis Cloud database.

Key expirations are suspended during Lua script execution in Redis.

When Redis reaches its memory limit, older data is evicted based on the selected eviction policy.

Under the no eviction policy, new values are not saved once the memory limit is reached.

Redis uses the AOF file to reconstruct the dataset upon restart if both are enabled.

Redis Cloud Essentials supports None, Single-Zone, and Multi-Zone high availability settings.

Organizations in finance, healthcare, and government can benefit from Redis Cloud BYOC for compliance.

A consumer group in Redis Streams allows multiple consumers to work together on the same stream.

A Redis Stream is an append-only log data structure that stores entries with unique IDs and key-value pairs.

AOF persistence logs every write operation received by Redis for data reconstruction.

Multi-AZ Deployment in Redis Cloud on AWS deploys databases across multiple Availability Zones for redundancy.

RDB persistence creates point-in-time snapshots of the dataset at specified intervals.

Use TLS encryption and adhere to Redis security guidelines to protect data and connections.

Redis Functions is an API for managing server-side code execution introduced in Redis 7.0.

Redis Sentinel is a monitoring solution for Redis instances that manages automatic failover and service discovery.

RedisJSON is a Redis module that adds JSON support to Redis.

OpenSSL development libraries, such as the libssl-dev package on Debian/Ubuntu, are required.

Active-Passive syncing requires the target Redis database to be hosted on Redis Cloud Pro.

Atomicity guarantees that multiple keys can be updated simultaneously without partial updates.

Redis on Kubernetes includes an auto-scaling feature for adjusting instances based on demand.

The command to execute a Lua script is EVAL.

The command to initiate a failover in Redis is 'FAILOVER'.

By default, Redis does not require authentication and listens to all network interfaces.

By default, Redis uses mutual TLS authentication requiring valid client certificates.

The default eviction policy in Redis is 'volatile-lru'. It can be changed using the maxmemory-policy configuration directive.

Redis Enterprise Software requires a commercial license for use.

The default maximum size of bulk strings in Redis is 512 megabytes.

Redis 7.0 introduces breaking changes, new features, and performance improvements not present in Redis 6.2.

Redis Cluster requires sharding configuration, while Redis Sentinel focuses on monitoring and failover settings.

Setting maxmemory-policy to noeviction returns out-of-memory errors for write commands when the limit is reached.

The evictionPolicy property defines the database eviction policy in Redis Enterprise.

The first step is to select an export storage destination and verify its readiness.

Pushed messages are array replies with message type, channel name, and payload.

Replication in Redis enhances scalability and data safety in production environments.

High availability features increase memory consumption due to additional memory allocation for replication.

The 'license' field specifies the license type for the module's distribution and use.

The 'license' field contains the license key for the Redis Enterprise cluster.

Redis allows keys up to a maximum size of 512 megabytes.

Redis allows a maximum key size and value size of 512 megabytes each.

A single Redis instance can handle up to 2^32 keys.

Redis string values have a maximum size limit of 512 megabytes.

Redis Cloud service supports key values with sizes up to 512 megabytes.

Redis strings have a maximum size limit of 512 megabytes for SETRANGE operations.

The MEMORY USAGE command returns the number of bytes used to store a specific key and its value in Redis.

Redis pub/sub provides at-most-once message delivery semantics.

RedisJSON 1.0 requires Redis version 4.0.0 or higher.

The 'noeviction' policy prevents new values from being saved when memory limits are reached.

The preferred method for mass importing data into Redis is generating a text file with Redis protocol commands.

The procedure involves backing up the RDB file and enabling AOF in the configuration.

Redis latency monitoring detects and analyzes slow server events to identify latency spikes.

The quorum is the number of Sentinel processes that must agree a master is unreachable to initiate failover.

Redis health checks should be performed periodically, such as every few seconds, in production.

At least four times the RAM size per node is recommended for persistent storage in production.

Lua scripts should only access keys explicitly provided as input arguments.

Redis Enterprise Software maintains compatibility with Redis Open Source licensing.

All keys used in Lua scripts must reside in the same hash slot in Redis Cloud cluster.

All operations in a transaction must be on keys in the same hash slot.

Clients must support Sentinel to utilize its features for high availability.

Encryption protects data confidentiality in Redis Cloud.

Redis Sentinel provides monitoring, notification, and automatic failover for Redis instances.

The producer in Redis Streams is responsible for adding new entries to the stream.

The _redis_ singleton provides an API to interact with the Redis server from Lua scripts.

RedisGraph v1.0.14 included a license update to the REDIS SOURCE AVAILABLE LICENSE AGREEMENT.

The MEMORY USAGE command has a time complexity of O(N).

Latency statistics reported by redis-cli --latency are expressed in milliseconds.

Redis Stack 7.2.2 includes RedisJSON version 2.6.7.

Redis Insight is distributed under the Server Side Public License (SSPL).

Redis open-source is licensed under three options: RSALv2, SSPLv1, or AGPLv3.

The Redis Query Engine features are licensed under RSALv2, SSPLv1, and AGPLv3.

Both RedisJSON and RediSearch modules must be installed.

Redis on Kubernetes integrates with Prometheus and Grafana for monitoring.

Ensure that all connections to the database are made through a private connectivity method.

RedisJSON 2.6 introduces support for the RESP3 protocol and new commands.

Redis 7.0 introduced Redis Functions and enhanced command capabilities.

Linux is recommended for deploying Redis in production environments.

Redis 7.0 includes performance optimizations for various data types and command execution.

Redis offers RDB for snapshots and AOF for logging every write operation.

It is recommended to enable replication settings for automatic failover and fault tolerance in Redis Cloud.

Generate strong and long passwords to make brute-force attacks infeasible.

Redis Cloud on AWS includes data encryption and compliance certifications.

Redis Cloud includes password-based authentication, role-based access control, and TLS for encrypted connections.

Set a password on the Redis instance using the requirepass configuration option to restrict access.

TLS encryption and adherence to Redis security guidelines are recommended for production deployments.

Redis 7.0 includes fixes for heap overflow vulnerabilities and denial-of-service issues.

Data larger than 512 megabytes should be split and stored across multiple keys.

The Redis port should be firewalled to prevent external access while allowing local access via the loopback interface.

Users should review breaking changes and update their applications to accommodate new behaviors in Redis 7.0.

Redis Enterprise for Kubernetes can use storage classes supported by block storage.

The Redis input and output CLI tool is available for migrating data to Redis.

Redis Software versions 7.8, 7.4, 7.2, 6.4, and 6.2 support Kubernetes.

Run SLOWLOG GET command to identify slow commands causing latency.

The compatible commands are DISCARD, EXEC, MULTI, UNWATCH, and WATCH.