span mode 實戰 ssi ever write 數據完整性 數據安全 view

redis.conf文件

1.Save a. save 秒鐘 寫操作次數

RDB是整個內存的壓縮過的Snapshot，RDB的數據結構，可以配置復合的快照觸發條件，
默認
是1分鐘內改了1萬次，
或5分鐘內改了10次，
或15分鐘內改了1次。

182 # Save the DB on disk: 184 # save <seconds> <changes> 186 # Will save the DB if both the given number of seconds and the given 187 # number of write operations against the DB occurred. 189 # In the example below the behaviour will be to save: 190 # after 900 sec (15 min) if at least 1 key changed 191 # after 300 sec (5 min) if at least 10 keys changed 192 # after 60 sec if at least 10000 keys changed

b.如果想禁用RDB持久化的策略，只要不設置任何save指令，或者給save傳入一個空字符串參數也可以

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
此時立馬執行，形成最新的dump文件

stop-writes-on-bgsave-error 如果配置成no，表示你不在乎數據不一致或者有其他的手段發現和控制

# 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

yes：出錯了就立即停止

rdbcompression rdbcompression：對於存儲到磁盤中的快照，可以設置是否進行壓縮存儲。如果是的話，redis會采用 LZF算法進行壓縮。如果你不想消耗CPU來進行壓縮的話，可以設置為關閉此功能

# 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

dbfilename

默認生成的rdb文件名

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

dir

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

實戰測試：

修改配置文件

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

兩分鐘10次操作

之後會生成一個dump.rdb文件，具體生成文件的默認名請修改：dbfilename

進行復制（備份）

模擬事故：

此時直接刪除所有的數據

此時再次重新登陸則是會顯示為空，即是存在dump.rdb文件

在管不redis時，迅速斬斷，保存文件dump.rdb

此時刪除之前的dump.rdb文件，並且把之前的dump_cp.rdb備份文件復制一份命名為dump.rdb 此時又可以進行之前的keys的值獲取

APPEND ONLY MODE追加

appendonly：默認開關狀態，可以同時和RDB一起開著

# 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
默認是關著的

appendfilename：默認的文件名

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

appendfsync

# 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：同步持久話每次發生數據變更立即記錄到磁盤，性能比較差但是數據完整性好
everysec：出場默認的推薦的，異步操作，每秒記錄，如果一秒內宕機，有數據丟失

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

no-appendfsync-on-rewrite：重寫時是否可以運用Appendfsync， 用默認no即可，保證數據安全性。

# 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

auto-aof-rewrite-min-size：設置重寫的基準值 auto-aof-rewrite-percentage：設置重寫的基準值

# 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

實戰測試： aof測試 首先開啟aof測試

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

此時已經生成文件，aof自動開啟

創造性的意外事件

查看appendonly.aof 發現已經記下了我們寫的命令 記錄了我們執行的每一條命令

重新啟動 裏面的內容為空

刪除appendonly.aof 的最後一句

此時重新啟動 獲取到我們之前的內容

假設出現下面的情況： appendonly.aof文件出錯：可能是網絡，斷電.......

此時RDB和AOF文件都在

此時啟動Redis

在dump.rdb文件完整的情況下，appendonly.aof文件出錯，說明後者的優先級大於前者

那麽此時的處理方式是：

redis-check-aof --fix appendonly.aof

再次重新啟動：

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