Redis的快照持久化-Redis学习笔记三

╰半橙微兮° 2022-02-05 12:25 243阅读 0赞

#  Redis持久化功能 #

redis为了内部数据的安全考虑，会把本身的数据以文件形式保存到硬盘中一份，在服务器重启之后会自动把硬盘的数据恢复到内存(redis)的里边。

数据保存到硬盘的过程就称为“持久化”效果。

## 1. snap shotting快照持久化 ##

该持久化默认开启，一次性把redis中全部的数据保存一份存储在硬盘中，如果数据非常多(10-20G)就不适合频繁进行该持久化操作。

下方是快照持久化在本地硬盘保留的数据备份文件（redis自动生成）：

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查看快照持久化的备份频率（打开redis.conf）：

################################ SNAPSHOTTING ################################# 
       # 
       # Save the DB on disk: 
       # 
       # save <seconds> <changes> 
       # 
       # Will save the DB if both the given number of seconds and the given 
       # number of write operations against the DB occurred. 
       # 
       # In the example below the behaviour will be to save: 
       # after 900 sec (15 min) if at least 1 key changed 
       # after 300 sec (5 min) if at least 10 keys changed 
       # after 60 sec if at least 10000 keys changed 
       # 
       # Note: you can disable saving at all commenting all the "save" lines. 
       # 
       # It is also possible to remove all the previously configured save 
       # points by adding a save directive with a single empty string argument 
       # like in the following example: 
       # 
       # save "" 
       
       save 900 1 
       save 300 10 
       save 60 10000

save 900 1          \#900 秒内如果超过 1 个 key 被修改，则发起快照保存

save 300 10        \#300秒超过10个key被修改，发起快照

save 60 10000    \#60秒超过10000个key被修改，发起快照

以上三个save的理解：

数据修改的频率非常高，备份的频率也高

数据修改的频率低，备份的频率也低

查看快照持久化文件的名字和存储位置（打开redis.conf）：

# The filename where to dump the DB 
       dbfilename dump.rdb 
       
       # The working directory. 
       # 
       # The DB will be written inside this directory, with the filename specified 
       # above using the 'dbfilename' configuration directive. 
       # 
       # The Append Only File will also be created inside this directory. 
       # 
       # Note that you must specify a directory here, not a file name. 
       dir ./

快照持久化 和 精细持久化  可以尽最大程度保证数据的安全：

![Center 1][]

### 2、手动发起快照持久化 ###

![Center 2][]

手动发起快照持久化

![Center 3][]

[Center]: /images/20220205/86c7946285114ffab5e3fda6686d7dfa.png
[Center 1]: /images/20220205/d2a34354eb41496b8ae505981f1ae051.png
[Center 2]: /images/20220205/ad8178f0cf8d4beb8caae0d171e63f3b.png
[Center 3]: /images/20220205/e98c26804f2946e28453157661e26be1.png