Redis Server is an open-source, in-memory data structure store that is widely used as a caching layer, message broker, and database. It is designed for high performance, low latency, and where data needs to be stored and retrieved quickly.
Redis is often referred to as a “data structure server” because it provides a variety of data structures like strings, lists, sets, sorted sets, hashes, bitmaps, and more, which can be manipulated using a rich set of commands.
Key features of Redis Server:
| 1 | Transactions: | Redis supports multi-command transactions, ensuring that a series of operations are executed as a single unit. |
| 2 | In-Memory Storage: | Redis stores all data in memory, which allows for extremely fast read and write operations. While this provides high performance, it also means that Redis is more suitable for datasets that can fit within the available memory. |
| 3 | Lua Scripting: | Redis supports Lua scripting, allowing you to execute custom logic directly on the server side. |
| 4 | Persistence: | Redis offers different mechanisms for data persistence, allowing you to save your data to disk so it can survive server restarts or failures. This persistence can be configured to be either asynchronous (using snapshotting or append-only files) or synchronous. |
| 5 | Atomic Operations: | Redis provides atomic operations on various data structures, ensuring that certain operations are executed without being interrupted by other commands. |
| 6 | Replication: | Redis supports master-slave replication, allowing you to create copies of your Redis dataset on multiple servers. This can be used for high availability and load distribution. |
| 7 | Pub/Sub Messaging: | Redis can be used as a publish-subscribe messaging system, enabling communication between different parts of an application or different applications altogether. |
| 8 | Caching: | One of the most common use cases for Redis is caching. It can store frequently accessed data in memory, reducing the need to fetch data from slower data stores like databases. |
Redis Server Provides numerous benefits, but it also has some limitations. Below are the pros and cons of Redis:
| pros | cons |
| (1) High performance: Redis is designed for speed, providing fast read and write performance due to its in-memory nature.
(2) Versatile data structures: Redis supports a wide range of data structures, making it suitable for a variety of uses beyond simple key-value storage. (3) Atomic Operations: Redis supports atomic operations on data structures, ensuring consistency and reliability in multi-step operations. (4) Caching: Redis is an excellent choice for caching frequently accessed data, reducing the load on primary data sources and improving application performance. (5) Pub/Sub Messaging: Redis’ publish-subscribe mechanism enables real-time communication between different parts of an application or between completely separate applications. (6) Replication and high availability: Redis provides master-slave replication for data redundancy and failover, increasing system reliability. (7) Persistence: Redis provides options for data persistence, allowing you to store data on a disk and retrieve it after a restart. (8) Lua Scripting: Redis supports server-side scripting, which allows you to perform complex operations without multiple round-trips to the server. (9) Geospatial Indexing: Redis has built-in support for geospatial data and can perform distance calculations and queries based on geographic coordinates. (10) Community and Ecosystem: Redis has a large and active community, with a rich ecosystem of client libraries and tools for various programming languages. |
(1) Memory usage:- Redis stores all data in memory, so it may not be suitable for datasets or datasets larger than available memory.
(2) Data Durability: While Redis offers persistent options, it does not provide as much durability as traditional disk-based databases. (3) Single-threaded: Redis is primarily single-threaded, which means it cannot fully utilize modern multi-core CPUs for certain workloads. (4) Complex queries: Redis is optimized for simple data access patterns; Complex questions are not his primary strength. (5) No SQL language: Redis does not provide a SQL-like query language, so advanced query and filtering capabilities are limited. (6) Limited use for complex transactions: While Redis supports transactions, it may not be suitable for very complex transaction scenarios. (7) Learning curve: Advanced features and data structures of Redis can have a steep learning curve for newcomers. (8) Scaling challenges: Scaling Redis horizontally across multiple nodes can involve more complexity than some other data stores. |
Install Redis-server:-
| Ubuntu | Centos |
| apt update apt install redis-server systemctl start redis-server systemctl status redis-server systemctl enable redis-server edit /etc/redis/redis.conf as per your requirement. |
dnf update dnf install redis systemctl start redis systemctl status redis systemctl enable revised/etc/redis.conf as per your requirement. |
OS tunning for Redis:-
| 1 | vm.swappiness=0 | # turn off swapping |
| 2 | net.ipv4.tcp_sack=1 | # enable selective acknowledgments |
| 3 | net.ipv4.tcp_timestamps=1 | # needed for selective acknowledgments |
| 4 | net.ipv4.tcp_window_scaling=1 | # scale the network window |
| 5 | net.ipv4.tcp_congestion_control=cubic | # Better congestion algorithm |
| 6 | net.ipv4.tcp_syncookies=1 | # enable syn cookies |
| 7 | net.ipv4.tcp_tw_recycle=1 | # Recycle sockets quickly |
| 8 | net.ipv4.tcp_max_syn_backlog=NUMBER | # backlog setting |
| 9 | net.core.somaxconn=NUMBER | # up the number of connections per port |
| 10 | net.core.rmem_max=NUMBER | # Up the receive buffer size |
| 11 | net.core.wmem_max=NUMBER | # Up the buffer size for all connections |
| 12 |
“redis.conf” changes:-
| bind 0.0.0.0 protected-mode yes port 6379 tcp-backlog 511 timeout 10 tcp-keepalive 300 daemonize yes supervised no pidfile /var/run/redis/redis-server.pid loglevel notice logfile /var/log/redis/redis-server.log databases 16 always-show-logo yes save 900 1 save 300 10 save 60 10000 stop-writes-on-bgsave-error yes rdbcompression no rdbchecksum yes dbfilename dump.rdb dir /var/lib/redis slave-serve-stale-data yes slave-read-only yes repl-diskless-sync no repl-diskless-sync-delay 5 repl-disable-tcp-nodelay no slave-priority 100 maxclients 102400 maxmemory 1gb maxmemory-policy allkeys-lru lazyfree-lazy-eviction no lazyfree-lazy-expire no lazyfree-lazy-server-del no slave-lazy-flush no appendonly no appendfilename “appendonly.aof” appendfsync everysec no-appendfsync-on-rewrite no auto-aof-rewrite-percentage 100 auto-aof-rewrite-min-size 512mb aof-load-truncated yes aof-use-rdb-preamble no lua-time-limit 5000 cluster-enabled yes #cluster-config-file nodes.conf cluster-node-timeout 5000 slowlog-log-slower-than 10000 slowlog-max-len 128 latency-monitor-threshold 0 notify-keyspace-events “” hash-max-ziplist-entries 512 hash-max-ziplist-value 64 list-max-ziplist-size -2 list-compress-depth 0 set-max-intset-entries 512 zset-max-ziplist-entries 128 zset-max-ziplist-value 64 hll-sparse-max-bytes 3000 activerehashing yes client-output-buffer-limit normal 0 0 0 client-output-buffer-limit slave 0 0 0 client-output-buffer-limit pubsub 32mb 8mb 60 hz 10 aof-rewrite-incremental-fsync yes replica-priority 100 replica-lazy-flush no stream-node-max-bytes 4096 stream-node-max-entries 100 dynamic-hz yes rename-command CONFIG “NIT-CONFIG” rename-command FLUSHDB “NIT-FLUSHDB” rename-command FLUSHALL “NIT-FLUSHALL” rename-command DEBUG “NIT-DEBUG” rename-command SHUTDOWN “NIT-SHUTDOWN” lua-time-limit 5000 |