search
HomeDatabaseRedisAOF method of Redis persistence

AOF method of Redis persistence

May 22, 2020 am 09:49 AM
redis

The RDB method of Redis cannot achieve persistence, but the AOF method can. If the data is important and loss will cause serious consequences, then the RDB method is obviously inappropriate and the AOF method should be used. The aof method is somewhat similar to mysql's binlog log, which only records new, modified, and deleted operations. The difference is that redis will rewrite the aof file every once in a while to reduce the size of the aof file.

AOF workflow

Here, why does the command need to be written to aof_buf first? Because if the aof file is written directly, then the performance depends entirely on Remove the IO performance of the hard disk. Writing aof_buf is to improve writing performance.

Configuration

appendonly: Whether to enable aof persistence mode, the default is no. If you want to enable it, change it to yes.

dir: aof file storage directory

appendfilename: aof file name

appendfsync: aof synchronization mode, there are three values, as follows:

  • always: synchronize every time a command is written, the data security is the highest, but the performance is poor

  • everysec: synchronize every second, the default method, high performance, safe The performance is okay

  • #no: The synchronization operation is left to the operating system, and the data security is the worst.

auto-aof-rewrite-percentage and auto-aof-rewrite-min-size These two configurations are related to the aof rewrite mechanism. Only when these two conditions are met at the same time can Will trigger the rewrite mechanism.

auto-aof-rewrite-min-size means that when rewriting, the file size must be larger than this value. The default value is 64mb

auto-aof-rewrite-percentage means the current file The size must be this much larger than the file size after the last rewrite.

AOF rewriting

The AOF rewriting mechanism of redis has two methods: manual triggering and automatic triggering. To trigger manually, enter the bgrewriteof command. Automatic triggering satisfies all two conditions mentioned above.

Why rewriting can reduce the file size? There are several situations:

  • Expired keys and deleted keys will no longer be recorded

  • Many single operations can be completed by one operation, such as lpush a, lpush b. After rewriting, it is lpush a b.

Let’s take a look at the aof rewriting process

AOF method of Redis persistence

  1. Execute the bgrewriteof command

  2. The main process forks a child process

  3. The original aof mechanism continues to run, and at the same time, new commands are also written into aof_rewrite_buf

  4. The child process generates a new aof file

  5. Notify the parent process that the new aof file has been generated successfully; append the commands in aof_rewrite_buf to the new aof file; replace the old aof file with the new aof file.

  6. After completing the above steps, the aof rewriting is completed.

Note that if there are multiple redis services on a server, it is best to separate their rewriting time to prevent excessive io and cpu competition.

The above is the detailed content of AOF method of Redis persistence. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Redis: Exploring Its Data Model and StructureRedis: Exploring Its Data Model and StructureApr 16, 2025 am 12:09 AM

Redis's data model and structure include five main types: 1. String: used to store text or binary data, and supports atomic operations. 2. List: Ordered elements collection, suitable for queues and stacks. 3. Set: Unordered unique elements set, supporting set operation. 4. Ordered Set (SortedSet): A unique set of elements with scores, suitable for rankings. 5. Hash table (Hash): a collection of key-value pairs, suitable for storing objects.

Redis: Classifying Its Database ApproachRedis: Classifying Its Database ApproachApr 15, 2025 am 12:06 AM

Redis's database methods include in-memory databases and key-value storage. 1) Redis stores data in memory, and reads and writes fast. 2) It uses key-value pairs to store data, supports complex data structures such as lists, collections, hash tables and ordered collections, suitable for caches and NoSQL databases.

Why Use Redis? Benefits and AdvantagesWhy Use Redis? Benefits and AdvantagesApr 14, 2025 am 12:07 AM

Redis is a powerful database solution because it provides fast performance, rich data structures, high availability and scalability, persistence capabilities, and a wide range of ecosystem support. 1) Extremely fast performance: Redis's data is stored in memory and has extremely fast read and write speeds, suitable for high concurrency and low latency applications. 2) Rich data structure: supports multiple data types, such as lists, collections, etc., which are suitable for a variety of scenarios. 3) High availability and scalability: supports master-slave replication and cluster mode to achieve high availability and horizontal scalability. 4) Persistence and data security: Data persistence is achieved through RDB and AOF to ensure data integrity and reliability. 5) Wide ecosystem and community support: with a huge ecosystem and active community,

Understanding NoSQL: Key Features of RedisUnderstanding NoSQL: Key Features of RedisApr 13, 2025 am 12:17 AM

Key features of Redis include speed, flexibility and rich data structure support. 1) Speed: Redis is an in-memory database, and read and write operations are almost instantaneous, suitable for cache and session management. 2) Flexibility: Supports multiple data structures, such as strings, lists, collections, etc., which are suitable for complex data processing. 3) Data structure support: provides strings, lists, collections, hash tables, etc., which are suitable for different business needs.

Redis: Identifying Its Primary FunctionRedis: Identifying Its Primary FunctionApr 12, 2025 am 12:01 AM

The core function of Redis is a high-performance in-memory data storage and processing system. 1) High-speed data access: Redis stores data in memory and provides microsecond-level read and write speed. 2) Rich data structure: supports strings, lists, collections, etc., and adapts to a variety of application scenarios. 3) Persistence: Persist data to disk through RDB and AOF. 4) Publish subscription: Can be used in message queues or real-time communication systems.

Redis: A Guide to Popular Data StructuresRedis: A Guide to Popular Data StructuresApr 11, 2025 am 12:04 AM

Redis supports a variety of data structures, including: 1. String, suitable for storing single-value data; 2. List, suitable for queues and stacks; 3. Set, used for storing non-duplicate data; 4. Ordered Set, suitable for ranking lists and priority queues; 5. Hash table, suitable for storing object or structured data.

How to implement redis counterHow to implement redis counterApr 10, 2025 pm 10:21 PM

Redis counter is a mechanism that uses Redis key-value pair storage to implement counting operations, including the following steps: creating counter keys, increasing counts, decreasing counts, resetting counts, and obtaining counts. The advantages of Redis counters include fast speed, high concurrency, durability and simplicity and ease of use. It can be used in scenarios such as user access counting, real-time metric tracking, game scores and rankings, and order processing counting.

How to use the redis command lineHow to use the redis command lineApr 10, 2025 pm 10:18 PM

Use the Redis command line tool (redis-cli) to manage and operate Redis through the following steps: Connect to the server, specify the address and port. Send commands to the server using the command name and parameters. Use the HELP command to view help information for a specific command. Use the QUIT command to exit the command line tool.

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. How to Fix Audio if You Can't Hear Anyone
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Chat Commands and How to Use Them
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

VSCode Windows 64-bit Download

VSCode Windows 64-bit Download

A free and powerful IDE editor launched by Microsoft

DVWA

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

SublimeText3 Linux new version

SublimeText3 Linux new version

SublimeText3 Linux latest version

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.