Redis Glossary

Redis is an open source, key-value database built with an in-memory design that emphasizes speed. It has support for rich data types, atomic operations, and Lua scripting.


This glossary defines the core concepts behind Redis to help build your mental model of how Redis work and understand what the documentation is referring to when it uses certain terminology.

ACID compliance is a set of database characteristics consisting of Atomicity, Consistency, Isolation, and Durability that ensure that database transactions are completed efficiently.
ACL
An access control list, or ACL, is a list of user permissions that controls access to a system resource.
Cache hit ratio is a metric that measures the efficiency of key retrieval in a database.
Connection pooling is a cache of database connections used for future requests to the database as required.
Connection status metric is a metric that measures the number of threads created, connected, and running in relation to a database’s connection limit.
A connection string is a string of characters that provides necessary information and parameters to establish a connection between a software application and the database. Connection strings are considered sensitive information and we recommend handling them securely, such as by avoiding hardcoding the string into the application’s code or configuration files.
CPU
A central processing unit, also called a processor or CPU, is an essential piece of computer hardware that executes the instructions from a computer program.
A data eviction policy specifies what happens when a database reaches its memory limit.
Database as a Service, Managed Database Service, or DBaaS for short, is a cloud service that allows users to access a cloud database system without having a personal cloud data system on a subscription basis.
In a denial-of-service (DoS) attack, a threat actor renders information systems, devices, or other network resources inaccessible by overwhelming the target with malicious traffic. A distributed denial-of-service (DDoS) attack is a type of DoS attack where the overloading traffic originates from multiple attacking machines, amplifying the severity of the attack.
Failover is a high availability (HA) mechanism that monitors servers for failures and reroutes traffic or operations to a redundant server when the primary server fails.
High Availability (HA) is an approach to infrastructure design focusing on reducing downtime and eliminating single points of failure.
Hot standby is the act of listening for when a primary node fails in order for the standby node to take its place.
IP
The Internet Protocol (IP) is a communications protocol used to connect computers across a network, specifically the Internet. IP consists of rules and regulations for transmission of packets across a network including routing and addressing. IP ensures that the packets of data that travel across a network arrives at the correct location.
Linux Unified Key Setup (LUKS) is an open source disk encryption specification for block storage devices.
Machine type is the set of virtualized hardware resources used for a virtual machine (VM) instance.
Node plan, database or cluster configuration is the hardware plan for node specifications.
Operations throughput metric is a measurement of throughput of fetch, insert, update, and delete operations across all databases on the server.
Point-in-time recovery, or PITR for short, ensures that automatic backups are made in order to restore or recover data made in a previous state of the server.
A port is a communication endpoint of a network connection. A port is identified using a port number for each transport protocol.
RAM
Random-Access Memory, or RAM, is a memory storage made to store and access memory on a short-term basis.
A read-only node is a replica of the cluster’s primary node.
A standby node is a node that is set aside idling on hot standby.
Tag
Tags are keywords associated with resources which help with managing resource ownership and organize lookups and actions on resources.
TTL
TTL, also known as time to live or hop limit, is the amount of time (also called hops) that a packet exists before being discarded by a router. TTL limits the lifespan of data within a network through attaching a time limit to data.