redis 服务监控

数据统计 --stat

--stat 可以实时获取redis的重要统计信息，虽然info命令中的统计信息更全，但是能实时看到一些增量的数据对redis的运维还是有一些帮助的

$ redis-cli --stat
------- data ------ --------------------- load -------------------- - child -
keys       mem      clients blocked requests            connections
506        1015.00K 1       0       24 (+0)             7
506        1015.00K 1       0       25 (+1)             7
506        3.40M    51      0       60461 (+60436)      57
506        3.40M    51      0       146425 (+85964)     107
507        3.40M    51      0       233844 (+87419)     157
507        3.40M    51      0       321715 (+87871)     207
508        3.40M    51      0       408642 (+86927)     257
508        3.40M    51      0       497038 (+88396)     257

默认每秒打印一次数据统计, 可以用-i <interval>修改间隔

扫描大键 -–bigkeys

--bigkeys 使用了scan命令对redis的键进行采样，从中找到占用内存较大的键值，这些键可能是系统的瓶颈

$ redis-cli --bigkeys

# Scanning the entire keyspace to find biggest keys as well as
# average sizes per key type.  You can use -i 0.1 to sleep 0.1 sec
# per 100 SCAN commands (not usually needed).

[00.00%] Biggest string found so far 'key-419' with 3 bytes
[05.14%] Biggest list   found so far 'mylist' with 100004 items
[35.77%] Biggest string found so far 'counter:__rand_int__' with 6 bytes
[73.91%] Biggest hash   found so far 'myobject' with 3 fields

-------- summary -------

Sampled 506 keys in the keyspace!
Total key length in bytes is 3452 (avg len 6.82)

Biggest string found 'counter:__rand_int__' has 6 bytes
Biggest   list found 'mylist' has 100004 items
Biggest   hash found 'myobject' has 3 fields

504 strings with 1403 bytes (99.60% of keys, avg size 2.78)
1 lists with 100004 items (00.20% of keys, avg size 100004.00)
0 sets with 0 members (00.00% of keys, avg size 0.00)
1 hashs with 3 fields (00.20% of keys, avg size 3.00)
0 zsets with 0 members (00.00% of keys, avg size 0.00)

监控延迟情况 -–latency

例子：

[root@Redis ~]# redis-cli --latency
min: 0, max: 1, avg: 0.07 (824 samples)

--latency-history

–latency的执行结果只有一条，如果想以分时段的形式了解延迟信息，可以使用 --latency-history 选项：

$ redis-cli -h 127.0.0.1 -p 6379 --latency-history
min: 0, max: 2, avg: 0.27 (1301 samples) -- 15.01 seconds range
min: 0, max: 2, avg: 0.27 (1301 samples) -- 15.00 seconds range
.
.
.
min: 0, max: 1, avg: 0.28 (1308 samples) -- 15.00 seconds range

默认每15秒输出一次，可以通过参数 -i(单位秒) 控制时间间隔，比如：

$ redis-cli -h 127.0.0.1 -p 6379 --latency-history -i 1
min: 0, max: 1, avg: 0.27 (92 samples) -- 1.00 seconds range
min: 0, max: 1, avg: 0.23 (91 samples) -- 1.00 seconds range

--latency-dist

--latency-dist选项会使用统计图表的形式从控制台输出延迟统计信息

$ redis-cli --latency-dist

rdb文件远程备份 –-rdb

获取指定redis实例的rdb文件,保存到本地。

$ redis-cli --rdb /tmp/dump.rdb
SYNC sent to master, writing 13256 bytes to '/tmp/dump.rdb'
Transfer finished with success.

监视Redis执行的命令 monitor

$ redis-cli monitor
OK
1460100081.165665 [0 127.0.0.1:51706] "set" "foo" "bar"
1460100083.053365 [0 127.0.0.1:51707] "get" "foo"

monitor可以使用管道传递输出，我们能使用诸如grep之类的工具监视特定的模式。

模拟从机模式 --slave

--slave是把当前客户端模拟成当前redis节点的从节点，可以用来获当前redis节点的更新操作

合理的利用这个选项可以记录当前连接Redis节点的更新操作，这些更新操作可能是实际开发业务时需要的数据。

第一个客户端使用–slave选项，可以看到它会一直处于等待状态：

[root@Redis ~]# redis-cli --slave
SYNC with master, discarding 1765 bytes of bulk transfer...
SYNC done. Logging commands from master.
"PING"

当另一台客户端进行一些数据操作时：

127.0.0.1:6379> set baobao good
OK
127.0.0.1:6379> del baobao
(integer) 1

设置–-slave选项的客户端会出现这些操作的指示：

[root@Redis ~]# redis-cli --slave
SYNC with master, discarding 1765 bytes of bulk transfer...
SYNC done. Logging commands from master.
"PING"
"PING"
"PING"
"PING"
"PING"
"SELECT","0"
"set","baobao","good"
"PING"
"PING"
"del","baobao"