Redis RDB AOP
RDB 存储
优势
- 适合大规模的数据恢复
- 对数据完整性和一致性要求不高
劣势
- 在一定间隔时间做一次备份,所以如果redis意外down掉的话,就会丢失最后一次快照后的所有修改
- fork的时候,内存中的数据被克隆了一份,大致2倍的膨胀性需要考虑
RDB方式要比AOF方式更加的高效。
RDB的缺点是最后一次持久化后的数据可能丢失。
################################ 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 completely by commenting out all "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
dbfilename dump.rdb
dir ./
save
<seconds>
<changes>
<seconds>
:: 在多少秒内
<changes>
:: 执行多少次写操作满足条件进行一次数据快照
AOP 存储
优势
- 每修改同步:appendfsync always 同步持久化 每次发生数据变更会被立即记录到磁盘 性能较差但数据完整性比较好
- 每秒同步:appendfsync everysec 异步操作,每秒记录 如果一秒内宕机,有数据丢失
- 不同步:appendfsync no 从不同步
劣势
- 相同数据集的数据而言aof文件要远大于rdb文件,恢复速度慢于rdb
- aof运行效率要慢于rdb,每秒同步策略效率较好,不同步效率和rdb相同
AOP 备份 规则将所有写的操作记录下来达到备份的效果
############################## APPEND ONLY MODE ###############################
# By default Redis asynchronously dumps the dataset on disk. This mode is
# good enough in many applications, but an issue with the Redis process or
# a power outage may result into a few minutes of writes lost (depending on
# the configured save points).
#
# The Append Only File is an alternative persistence mode that provides
# much better durability. For instance using the default data fsync policy
# (see later in the config file) Redis can lose just one second of writes in a
# dramatic event like a server power outage, or a single write if something
# wrong with the Redis process itself happens, but the operating system is
# still running correctly.
#
# AOF and RDB persistence can be enabled at the same time without problems.
# If the AOF is enabled on startup Redis will load the AOF, that is the file
# with the better durability guarantees.
#
# Please check http://redis.io/topics/persistence for more information.
appendonly no
# The name of the append only file (default: "appendonly.aof")
appendfilename "appendonly.aof"
# 同步策略
# 每修改一次同步到磁盘
# appendfsync always
# 每秒同步
appendfsync everysec
# 不同步
# appendfsync no
开启 AOP 存储需要将: appendonly no 改为 appendonly yes
修复备份数据( *.aof | *.rdb )
使用
Redis
工具 :redis-check-aof
redis-check-rdb
语法:
redis-check-aof
--fix
appendonly.aof