Redis配置檔案（2）SNAPSHOTTING快照/APPEND ONLY MODE追加
redis.conf檔案
1.Save
a. save 秒鐘 寫操作次數
RDB是整個記憶體的壓縮過的Snapshot，RDB的資料結構，可以配置複合的快照觸發條件， 預設 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，只要不設定任何save指令，或者給save傳入一個空字串引數也可以
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檔案
stop-writes-on-bgsave-error
如果配置成no，表示你不在乎資料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：對於儲存到磁碟中的快照，可以設定是否進行壓縮儲存。如果是的話，redis會採用
LZF演算法進行壓縮。如果你不想消耗CPU來進行壓縮的話，可以設定為關閉此功能
# 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
預設生成的rdb檔名
# 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：
修改配置檔案
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檔案，具體生成檔案的預設名請修改： dbfilename
進行復制（備份）
模擬事故：
此時直接刪除所有的資料
此時再次重新登陸則是會顯示為空，即是存在dump.rdb檔案
在管不redis時，迅速斬斷，儲存檔案dump.rdb
此時刪除之前的dump.rdb檔案，並且把之前的dump_cp.rdb備份檔案複製一份命名為dump.rdb
此時又可以進行之前的keys的值獲取
APPEND ONLY MODE追加
appendonly：預設開關狀態，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 預設是關著的
appendfilename：預設的檔名
# 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資料變更立即記錄到磁碟，效能比較差但是資料完整性好 everysec：出場預設的推薦的，非同步操作，每秒記錄，如果一秒內宕機，有資料丟失
# 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，
用預設no即可，保證資料安全性。
# 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：設定重寫的基準值
auto-aof-rewrite-percentage：設定重寫的基準值
# 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
此時已經生成檔案，aof自動開啟
創造性的意外事件
檢視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
裡面的內容為空
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檔案出錯：可能是網路，斷電.......
此時RDB和AOF檔案都在
此時啟動Redis
在dump.rdb檔案完整的情況下，appendonly.aof檔案出錯，說明後者的優先順序大於前者
那麼此時的處理方式是：
redis-check-aof --fix appendonly.aof
再次重新啟動：
