Redis配置文件（2）SNAPSHOTTING快照/APPEND ONLY MODE追加

RDB是整个内存的压缩过的Snapshot，RDB的数据结构，可以配置复合的快照触发条件，
默认
是1分钟内改了1万次，
或5分钟内改了10次，
或15分钟内改了1次。

194 #   Note: you can disable saving completely by commenting out all "save" lines.
195 #
196 #   It is also possible to remove all the previously configured save
197 #   points by adding a save directive with a single empty string argument
198 #   like in the following example:
199 #
200 #   save ""
202 save 900 1
203 save 300 10
204 save 60 10000

set key value1

save
此时立马执行，形成最新的dump文件

# However if you have setup your proper monitoring of the Redis server
# and persistence, you may want to disable this feature so that Redis will
# continue to work as usual even if there are problems with disk,
# permissions, and so forth.
stop-writes-on-bgsave-error yes

# Compress string objects using LZF when dump .rdb databases?
# For default that‘s set to ‘yes‘ as it‘s almost always a win.
# If you want to save some CPU in the saving child set it to ‘no‘ but
# the dataset will likely be bigger if you have compressible values or keys.
rdbcompression yes

# The filename where to dump the DB
dbfilename dump.rdb

# Note that you must specify a directory here, not a file name.
dir ./

200 #   save ""
202 save 900 1
203 save 120 10
204 save 60 10000

# 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
默认是关着的

# The name of the append only file (default: "appendonly.aof")
appendfilename "appendonly.aof"

# no: don‘t fsync, just let the OS flush the data when it wants. Faster.
# always: fsync after every write to the append only log. Slow, Safest.
# everysec: fsync only one time every second. Compromise.
always：同步持久话每次发生数据变更立即记录到磁盘，性能比较差但是数据完整性好
everysec：出场默认的推荐的，异步操作，每秒记录，如果一秒内宕机，有数据丢失

# More details please check the following article:
# http://antirez.com/post/redis-persistence-demystified.html
# If unsure, use "everysec".
# appendfsync always
appendfsync everysec

# If you have latency problems turn this to "yes". Otherwise leave it as
# "no" that is the safest pick from the point of view of durability.
no-appendfsync-on-rewrite no

# This base size is compared to the current size. If the current size is
# bigger than the specified percentage, the rewrite is triggered. Also
# you need to specify a minimal size for the AOF file to be rewritten, this
# is useful to avoid rewriting the AOF file even if the percentage increase
# is reached but it is still pretty small.
# Specify a percentage of zero in order to disable the automatic AOF
# rewrite feature.
auto-aof-rewrite-percentage 100
auto-aof-rewrite-min-size 64mb

# Please check http://redis.io/topics/persistence for more information.
appendonly yes

redis-check-aof --fix appendonly.aof