Redis配置文件(2)SNAPSHOTTING快照/APPEND ONLY MODE追加
阿新 • • 發佈:2018-12-02
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 # continueto 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