Redis的快照持久化-Redis学习笔记三

 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redis全部的数据保存一份存储在硬盘中,如果数据非常多(10-20G)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):

Redis的快照持久化-Redis学习笔记三_第1张图片

查看快照持久化的备份频率(打开redis.conf):

################################ SNAPSHOTTING  #################################
#
# Save the DB on disk:
#
#   save  
#
#   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 个 key 被修改,则发起快照保存

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

save 60 10000    #60秒超过10000key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:

Redis的快照持久化-Redis学习笔记三_第2张图片

2、手动发起快照持久化

Redis的快照持久化-Redis学习笔记三_第3张图片

手动发起快照持久化

Redis的快照持久化-Redis学习笔记三_第4张图片

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