Redis的快照持久化-RDB与AOF

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）：



查看快照持久化的备份频率（打开redis.conf）：

[csharp] view plain copy

print?

################################ 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）：

[csharp] view plain copy

print?

# 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：

2、手动发起快照持久化

手动发起快照持久化