Redis基础知识（学习笔记15--持久化 (1)）

save

bgsave

lastsave

################################ SNAPSHOTTING  ################################

# Save the DB to disk.
#
# save <seconds> <changes> [<seconds> <changes> ...]
#
# Redis will save the DB if the given number of seconds elapsed and it
# surpassed the given number of write operations against the DB.
#
# Snapshotting can be completely disabled with a single empty string argument
# as in following example:
#
# save ""
#
# Unless specified otherwise, by default Redis will save the DB:
#   * After 3600 seconds (an hour) if at least 1 change was performed
#   * After 300 seconds (5 minutes) if at least 100 changes were performed
#   * After 60 seconds if at least 10000 changes were performed
#
# You can set these explicitly by uncommenting the following line.
# 下面是默认持久规则
# save 3600 1 300 100 60 10000

# 如果60s内执行了10000次的变更操作，则执行一次bgsave;如果这个条件不成立，例如，60s内就执行了9990次， 那么就检查300s内，是否变化了100次+，如果满足，则bgsave
# 一次；如果还是不满足，例如 5分钟（300s）,就执行了99次，那么怎看上面的规则；判断 3600s,变化次数是否不小于1次（至少一次），如果至少一次，则触发 bgsave。
# 即：这儿定义的触发 持久化的条件：依次判断 【60 10000】？【300 100】? 【3600 1】？ 。要求是越来越低了。

# By default Redis will stop accepting writes if RDB snapshots are enabled
# (at least one save point) and the latest background save failed.
# This will make the user aware (in a hard way) that data is not persisting
# on disk properly, otherwise chances are that no one will notice and some
# disaster will happen.
#
# If the background saving process will start working again Redis will
# automatically allow writes again.
#
# 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
## 上面的参数 是 bgsave 遇到错误时，是否阻止写入的参数


# Compress string objects using LZF when dump .rdb databases?
# By default compression is enabled 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
##是否采用压缩的参数

# Since version 5 of RDB a CRC64 checksum is placed at the end of the file.
# This makes the format more resistant to corruption but there is a performance
# hit to pay (around 10%) when saving and loading RDB files, so you can disable it
# for maximum performances.
#
# RDB files created with checksum disabled have a checksum of zero that will
# tell the loading code to skip the check.
rdbchecksum yes
##备份校验的参数

# Enables or disables full sanitization【净化；消毒；卫生处理；】 checks for ziplist and listpack etc when
# loading an RDB or RESTORE payload. This reduces the chances of a assertion or
# crash later on while processing commands.
# Options:
#   no         - Never perform full sanitization
#   yes        - Always perform full sanitization
#   clients    - Perform full sanitization only for user connections.
#                Excludes: RDB files, RESTORE commands received from the master
#                connection, and client connections which have the
#                skip-sanitize-payload ACL flag.
# The default should be 'clients' but since it currently affects cluster
# resharding via MIGRATE, it is temporarily set to 'no' by default.
#
# sanitize-dump-payload no

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

# Remove RDB files used by replication in instances without persistence
# enabled. By default this option is disabled, however there are environments
# where for regulations【法规；规则；章程】 or other security concerns【忧虑；担心】, RDB files persisted on
# disk by masters in order to feed replicas, or stored on disk by replicas
# in order to load them for the initial synchronization, should be deleted
# ASAP【as soon as possible】. Note that this option ONLY WORKS in instances that have both AOF
# and RDB persistence disabled, otherwise is completely ignored.--注意生效的前提。
#
# An alternative (and sometimes better) way to obtain the same effect is
# to use diskless replication on both master and replicas instances. However
# in the case of replicas, diskless is not always an option.
rdb-del-sync-files no

# The working directory. ##这一part是说设置目录的
#
# The DB will be written inside this directory, with the filename specified
# above using the 'dbfilename' configuration directive.
#
# The Append Only File will also be created inside this directory. ##注意：对AOF文件（备份方式）同样有用
#
# Note that you must specify a directory here, not a file name.
dir ./

################################# REPLICATION #################################