MongoDB从MMAPv1在线迁移至WiredTiger引擎

发表于 | 分类于
字数统计: | 阅读时长 ≈

前言

MongoDB是一个开源的文档型数据库，介于关系数据库和非关系数据库之间，是非关系数据库中功能最丰富，最像关系数据库的。它支持的数据结构非常松散，是类似json的bson格式，因此可以存储比较复杂的数据类型。Mongo最大的特点是它支持的查询语言非常强大，其语法有点类似于面向对象的查询语言，几乎可以实现类似关系数据库单表查询的绝大部分功能，而且还支持对数据建立索引。

存储引擎

存储引擎是MongoDB的核心组件，负责管理数据如何存储在硬盘和内存上。从MongoDB3.0版本开始，MongoDB支持多数据存储引擎，如WiredTiger，MMAPv1，In-Memory等，每个存储引擎都有自己的优势，percona版本还支持RocksDB引擎。从3.2版本开始，WiredTiger成为了默认的存储引擎，在之前版本MMAPv1为默认存储引擎。这两种引擎在目前的使用量占比最大。

WiredTiger、MMAPv1对比

性能、性能

MMAPv1引擎使用的是表级锁，当单个集合上有并发操作时，吞吐会受限制。
Wiredtiger引擎使用文档级锁，通过多版本并发控制，带来并发和吞吐的提高。

压缩、加密

MMAPv1引擎要求数据在内存和在磁盘的形式一致(map磁盘内存映射)，因此不支持压缩和加密。
Wiredtiger引擎支持对所有集合和索引进行Block压缩和前缀压缩，可以大大节省存储空间。但是消耗额外的CPU执行数据压缩和解压缩的操作。

存储方式

MMAPv1引擎在数据库级别配置文件，数据库中的所有集合和索引都混合存储在数据库文件中，即使删掉了某个集合或者索引，占用的磁盘空间也很难回收。
WiredTiger引擎在集合和索引级别分配文件，数据库中的所有集合和索引都存储在单独的文件中，集合或者索引删除后，磁盘空间方便回收。

内存使用

MMAPv1引擎消耗内存大，无有效控制手段。
WiredTiger引擎支持内存使用空间配置，可通过storage.wiredTiger.engineConfig.cacheSizeGB参控制MongoDB所能使用的最大内存。

准备

操作系统：centos 6.5 x86_64

迁移

变更存储引擎的常见方式有2种，分别是停机和不停机。本文只介绍在不停机的情况下从MMAPv1引擎副本集迁移至WiredTiger引擎副本集。

安装

注意：

迁移的成功取决于oplog的大小是否能够满足从库完全初始化数据。

首先安装好mongodb，并依次启动，实例以3.4.4版本为例，端口分别是27017/28017/29017，部署在一台服务器，具体安装步骤省略。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongod -f /hwdata/data/mongodb1/conf/mongodb.conf 
note: noprealloc may hurt performance in many applications
about to fork child process, waiting until server is ready for connections.
forked process: 14873
child process started successfully, parent exiting
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb2/bin/mongod -f /hwdata/data/mongodb2/conf/mongodb.conf   
note: noprealloc may hurt performance in many applications
about to fork child process, waiting until server is ready for connections.
forked process: 14894
child process started successfully, parent exiting
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb3/bin/mongod -f /hwdata/data/mongodb3/conf/mongodb.conf   
note: noprealloc may hurt performance in many applications
about to fork child process, waiting until server is ready for connections.
forked process: 14919
child process started successfully, parent exiting
[root@iZuf6c08fdv8duubho2b0rZ ~]# netstat -tunlp|grep mongo
tcp        0      0 0.0.0.0:27017               0.0.0.0:*                   LISTEN      14873/mongod        
tcp        0      0 0.0.0.0:28017               0.0.0.0:*                   LISTEN      14894/mongod        
tcp        0      0 0.0.0.0:29017               0.0.0.0:*                   LISTEN      14919/mongod

配置文件

详情的配置文件如下：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb1/conf/mongodb.conf 
dbpath=/hwdata/data/mongodb1/data
logpath=/hwdata/data/mongodb1/logs/mongodb.log
pidfilepath=/hwdata/data/mongodb1/logs/mongodb.pid
directoryperdb=true
logappend=true
port=27017
fork=true
noprealloc=true
maxConns=10000
profile=1
slowms=100
journal=true
replSet=jiessie
storageEngine=mmapv1
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb2/conf/mongodb.conf  
dbpath=/hwdata/data/mongodb2/data
logpath=/hwdata/data/mongodb2/logs/mongodb.log
pidfilepath=/hwdata/data/mongodb2/logs/mongodb.pid
directoryperdb=true
logappend=true
port=28017
fork=true
noprealloc=true
maxConns=10000
profile=1
slowms=100
journal=true
replSet=jiessie
storageEngine=mmapv1
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb3/conf/mongodb.conf  
dbpath=/hwdata/data/mongodb3/data
logpath=/hwdata/data/mongodb3/logs/mongodb.log
pidfilepath=/hwdata/data/mongodb3/logs/mongodb.pid
directoryperdb=true
logappend=true
port=29017
fork=true
noprealloc=true
maxConns=10000
profile=1
slowms=100
journal=true
replSet=jiessie
storageEngine=mmapv1

搭建副本集

登录其中一个实例，这里以27017为例子，搭建副本

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
> cfg = {_id: "jiessie", members: [{_id: 0, host: "192.168.7.50:27017",priority:3},{_id: 1, host: "192.168.7.50:28017",priority:2},{_id: 2, host: "192.168.7.50:29017",priority:3}]};
{
        "_id" : "jiessie",
        "members" : [
                {
                        "_id" : 0,
                        "host" : "192.168.7.50:27017",
                        "priority" : 3
                },
                {
                        "_id" : 1,
                        "host" : "192.168.7.50:28017",
                        "priority" : 2
                },
                {
                        "_id" : 2,
                        "host" : "192.168.7.50:29017",
                        "priority" : 3
                }
        ]
}
> rs.initiate(cfg);
{ "ok" : 1 }
jiessie:SECONDARY> 
jiessie:PRIMARY> rs.status();
{
        "set" : "jiessie",
        "date" : ISODate("2017-07-21T09:47:24.215Z"),
        "myState" : 1,
        "term" : NumberLong(1),
        "heartbeatIntervalMillis" : NumberLong(2000),
        "optimes" : {
                "lastCommittedOpTime" : {
                        "ts" : Timestamp(1500630436, 1),
                        "t" : NumberLong(1)
                },
                "appliedOpTime" : {
                        "ts" : Timestamp(1500630436, 1),
                        "t" : NumberLong(1)
                },
                "durableOpTime" : {
                        "ts" : Timestamp(1500630436, 1),
                        "t" : NumberLong(1)
                }
        },
        "members" : [
                {
                        "_id" : 0,
                        "name" : "192.168.7.50:27017",
                        "health" : 1,
                        "state" : 1,
                        "stateStr" : "PRIMARY",
                        "uptime" : 1056,
                        "optime" : {
                                "ts" : Timestamp(1500630436, 1),
                                "t" : NumberLong(1)
                        },
                        "optimeDate" : ISODate("2017-07-21T09:47:16Z"),
                        "infoMessage" : "could not find member to sync from",
                        "electionTime" : Timestamp(1500630354, 1),
                        "electionDate" : ISODate("2017-07-21T09:45:54Z"),
                        "configVersion" : 1,
                        "self" : true
                },
                {
                        "_id" : 1,
                        "name" : "192.168.7.50:28017",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 99,
                        "optime" : {
                                "ts" : Timestamp(1500630436, 1),
                                "t" : NumberLong(1)
                        },
                        "optimeDurable" : {
                                "ts" : Timestamp(1500630436, 1),
                                "t" : NumberLong(1)
                        },
                        "optimeDate" : ISODate("2017-07-21T09:47:16Z"),
                        "optimeDurableDate" : ISODate("2017-07-21T09:47:16Z"),
                        "lastHeartbeat" : ISODate("2017-07-21T09:47:22.597Z"),
                        "lastHeartbeatRecv" : ISODate("2017-07-21T09:47:23.554Z"),
                        "pingMs" : NumberLong(0),
                        "syncingTo" : "192.168.7.50:29017",
                        "configVersion" : 1
                },
                {
                        "_id" : 2,
                        "name" : "192.168.7.50:29017",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 99,
                        "optime" : {
                                "ts" : Timestamp(1500630436, 1),
                                "t" : NumberLong(1)
                        },
                        "optimeDurable" : {
                                "ts" : Timestamp(1500630436, 1),
                                "t" : NumberLong(1)
                        },
                        "optimeDate" : ISODate("2017-07-21T09:47:16Z"),
                        "optimeDurableDate" : ISODate("2017-07-21T09:47:16Z"),
                        "lastHeartbeat" : ISODate("2017-07-21T09:47:22.597Z"),
                        "lastHeartbeatRecv" : ISODate("2017-07-21T09:47:23.527Z"),
                        "pingMs" : NumberLong(0),
                        "syncingTo" : "192.168.7.50:27017",
                        "configVersion" : 1
                }
        ],
        "ok" : 1
}
jiessie:PRIMARY>

查看存储引擎

登录其中一个实例，这里以27017为例子，当出现mmapv1时，代表当前使用存储引擎为mmapv1

1
2
3
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo --eval "db.serverStatus()"|grep name
                "name" : "mmapv1",
[root@iZuf6c08fdv8duubho2b0rZ ~]#

测试副本集

登录27017的主库，插入数据，在其他节点上查看

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo 
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
jiessie:PRIMARY> show dbs;
admin   0.078GB
local  12.072GB
jiessie:PRIMARY> use test11;
switched to db test11
jiessie:PRIMARY> db.tmp11.insert({"id":"11"});
WriteResult({ "nInserted" : 1 })
jiessie:PRIMARY> db.tmp11.find();
{ "_id" : ObjectId("5971ced335d36a3364107ac7"), "id" : "11" }
jiessie:PRIMARY> exit
bye
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:28017
MongoDB shell version v3.4.4
connecting to: localhost:28017
MongoDB server version: 3.4.4
jiessie:SECONDARY> rs.slaveOk();
jiessie:SECONDARY> use test11;
switched to db test11
jiessie:SECONDARY> db.tmp11.find();
{ "_id" : ObjectId("5971ced335d36a3364107ac7"), "id" : "11" }
jiessie:SECONDARY> exit
bye
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:29017
MongoDB shell version v3.4.4
connecting to: localhost:29017
MongoDB server version: 3.4.4
jiessie:SECONDARY> use test11;
switched to db test11
jiessie:SECONDARY> rs.slaveOk();
jiessie:SECONDARY> db.tmp11.find();
{ "_id" : ObjectId("5971ced335d36a3364107ac7"), "id" : "11" }
jiessie:SECONDARY> exit

迁移步骤

1
2
3
4
5
将29017的从节点设置为隐藏节点，不再成为主，对应用不可见
把29017的节点存储引擎从MMAPv1设置为WiredTiger，删除原MMAPv1数据，重新加入副本集中
当29017的WiredTiger节点从主节点初始化数据成功后，依次将其他从节点的引擎修改为的WiredTiger
当所有从节点的引擎修改为WiredTiger后，在主节点执行rs.stepdown()将主降级，触发在其他从节点选举新主
再将原主库按照以上的方式将引擎从MMAPv1设置为WiredTiger

详情请参考：http://docs.mongoing.com/manual-zh/tutorial/configure-a-hidden-replica-set-member.html

开始迁移

副本集的架构下，所有节点之间都是同步的，即使存储引擎不同也不受影响。
实验中的副本集端口分别为27017/28017/29017，其中主节点为27017，28017和29017为从节点。
27017权重为3，28017权重为2，29017权重为1。

步骤最后一项，将原主库引擎从MMAPv1设置为WiredTiger，可在原主库上执行rs.stepDown()触发选举，也可提高其他从节点的权重，需要高于主节点。

29017实例

设置节点隐藏
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
jiessie:PRIMARY> cfg = rs.config();
{
        "_id" : "jiessie",
        "version" : 1,
        "protocolVersion" : NumberLong(1),
        "members" : [
                {
                        "_id" : 0,
                        "host" : "192.168.7.50:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 3,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 1,
                        "host" : "192.168.7.50:28017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 2,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 2,
                        "host" : "192.168.7.50:29017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 3,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                }
        ],
        "settings" : {
                "chainingAllowed" : true,
                "heartbeatIntervalMillis" : 2000,
                "heartbeatTimeoutSecs" : 10,
                "electionTimeoutMillis" : 10000,
                "catchUpTimeoutMillis" : 2000,
                "getLastErrorModes" : {

                },
                "getLastErrorDefaults" : {
                        "w" : 1,
                        "wtimeout" : 0
                },
                "replicaSetId" : ObjectId("5971cd4835e57f0331e944c8")
        }
}
jiessie:PRIMARY> cfg.members[2].host;
192.168.7.50:29017
jiessie:PRIMARY> cfg.members[2].priority = 0;       #优化级降为0，不再参数选主
0
jiessie:PRIMARY> cfg.members[2].hidden = true;      #对应用隐藏
true
jiessie:PRIMARY> rs.reconfig(cfg);
{ "ok" : 1 }
jiessie:PRIMARY>
修改引擎，删除原数据
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:29017
MongoDB shell version v3.4.4
connecting to: localhost:29017
MongoDB server version: 3.4.4
jiessie:SECONDARY> rs.slaveOk();
jiessie:SECONDARY> use admin;
switched to db admin
jiessie:SECONDARY> db.shutdownServer();                                                      #关闭服务
server should be down...
[root@iZuf6c08fdv8duubho2b0rZ ~]# rm -rf /hwdata/data/mongodb3/data/*                        #删除原引擎数据
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb3/conf/mongodb.conf |grep sto      #查看原配置
storageEngine=mmapv1
[root@iZuf6c08fdv8duubho2b0rZ ~]# sed -i 's@storageEngine=mmapv1@storageEngine=wiredTiger@g' /hwdata/data/mongodb3/conf/mongodb.conf    #修改配置文件的引擎部分
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb3/conf/mongodb.conf |grep sto      #查看新配置
storageEngine=wiredTiger
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb3/bin/mongod -f /hwdata/data/mongodb3/conf/mongodb.conf     #启动服务
note: noprealloc may hurt performance in many applications
about to fork child process, waiting until server is ready for connections.
forked process: 613
child process started successfully, parent exiting
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb3/bin/mongo localhost:29017 --eval "db.serverStatus()"|grep '"name"'    #验证是否修改成功
                "name" : "wiredTiger",
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb3/bin/mongo localhost:29017
MongoDB shell version v3.4.4
connecting to: localhost:29017
MongoDB server version: 3.4.4
jiessie:SECONDARY> exit                     #验证初始化同步是否成功，SECONDARY状态表示已经是从节点
加入副本集
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
jiessie:PRIMARY> cfg = rs.config();
{
        "_id" : "jiessie",
        "version" : 2,
        "protocolVersion" : NumberLong(1),
        "members" : [
                {
                        "_id" : 0,
                        "host" : "192.168.7.50:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 3,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 1,
                        "host" : "192.168.7.50:28017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 2,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 2,
                        "host" : "192.168.7.50:29017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : true,
                        "priority" : 0,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                }
        ],
        "settings" : {
                "chainingAllowed" : true,
                "heartbeatIntervalMillis" : 2000,
                "heartbeatTimeoutSecs" : 10,
                "electionTimeoutMillis" : 10000,
                "catchUpTimeoutMillis" : 2000,
                "getLastErrorModes" : {

                },
                "getLastErrorDefaults" : {
                        "w" : 1,
                        "wtimeout" : 0
                },
                "replicaSetId" : ObjectId("5971cd4835e57f0331e944c8")
        }
}
jiessie:PRIMARY> cfg.members[2].hidden=false;       #加入副本集，对应用可见，其中[2]表示29017端口
false
jiessie:PRIMARY> cfg.members[2].priority = 1;       #修改为之前的优先级
1
jiessie:PRIMARY> rs.reconfig(cfg);
{ "ok" : 1 }
jiessie:PRIMARY>

28017实例

设置节点隐藏
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
jiessie:PRIMARY> cfg = rs.config();
{
        "_id" : "jiessie",
        "version" : 4,
        "protocolVersion" : NumberLong(1),
        "members" : [
                {
                        "_id" : 0,
                        "host" : "192.168.7.50:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 3,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 1,
                        "host" : "192.168.7.50:28017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 2,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 2,
                        "host" : "192.168.7.50:29017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                }
        ],
        "settings" : {
                "chainingAllowed" : true,
                "heartbeatIntervalMillis" : 2000,
                "heartbeatTimeoutSecs" : 10,
                "electionTimeoutMillis" : 10000,
                "catchUpTimeoutMillis" : 2000,
                "getLastErrorModes" : {

                },
                "getLastErrorDefaults" : {
                        "w" : 1,
                        "wtimeout" : 0
                },
                "replicaSetId" : ObjectId("5971cd4835e57f0331e944c8")
        }
}
jiessie:PRIMARY> cfg.members[1].host
192.168.7.50:28017
jiessie:PRIMARY> cfg.members[1].priority = 0;
0
jiessie:PRIMARY> cfg.members[1].hidden = true;
true
jiessie:PRIMARY> rs.reconfig(cfg);
{ "ok" : 1 }
jiessie:PRIMARY>
修改引擎，删除原数据
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:28017
MongoDB shell version v3.4.4
connecting to: localhost:28017
MongoDB server version: 3.4.4
jiessie:SECONDARY> rs.slaveOk();
jiessie:SECONDARY> use admin;
switched to db admin
jiessie:SECONDARY> db.shutdownServer();                                                      #关闭服务
server should be down...
[root@iZuf6c08fdv8duubho2b0rZ ~]# rm -rf /hwdata/data/mongodb2/data/*                        #删除原引擎数据
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb2/conf/mongodb.conf |grep sto      #查看原配置
storageEngine=mmapv1
[root@iZuf6c08fdv8duubho2b0rZ ~]# sed -i 's@storageEngine=mmapv1@storageEngine=wiredTiger@g' /hwdata/data/mongodb2/conf/mongodb.conf    #修改配置文件的引擎部分
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb2/conf/mongodb.conf |grep sto      #查看新配置
storageEngine=wiredTiger
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb2/bin/mongod -f /hwdata/data/mongodb2/conf/mongodb.conf     #启动服务
note: noprealloc may hurt performance in many applications
about to fork child process, waiting until server is ready for connections.
forked process: 1275
child process started successfully, parent exiting
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb2/bin/mongo localhost:28017 --eval "db.serverStatus()"|grep '"name"'    #验证是否修改成功
                "name" : "wiredTiger",
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb2/bin/mongo localhost:28017
MongoDB shell version v3.4.4
connecting to: localhost:28017
MongoDB server version: 3.4.4
jiessie:SECONDARY> exit                     #验证初始化同步是否成功，SECONDARY状态表示已经是从节点
加入副本集
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo 
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
jiessie:PRIMARY> cfg = rs.config();
{
        "_id" : "jiessie",
        "version" : 5,
        "protocolVersion" : NumberLong(1),
        "members" : [
                {
                        "_id" : 0,
                        "host" : "192.168.7.50:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 3,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 1,
                        "host" : "192.168.7.50:28017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : true,
                        "priority" : 0,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 2,
                        "host" : "192.168.7.50:29017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                }
        ],
        "settings" : {
                "chainingAllowed" : true,
                "heartbeatIntervalMillis" : 2000,
                "heartbeatTimeoutSecs" : 10,
                "electionTimeoutMillis" : 10000,
                "catchUpTimeoutMillis" : 2000,
                "getLastErrorModes" : {

                },
                "getLastErrorDefaults" : {
                        "w" : 1,
                        "wtimeout" : 0
                },
                "replicaSetId" : ObjectId("5971cd4835e57f0331e944c8")
        }
}
jiessie:PRIMARY> cfg.members[1].hidden = false;     #加入副本集，对应用可见，其中[1]表示28017端口
false
jiessie:PRIMARY> cfg.members[1].priority = 2;       #修改为之前的优先级
2
jiessie:PRIMARY> rs.reconfig(cfg);
{ "ok" : 1 }
jiessie:PRIMARY>

27017实例

设置节点隐藏
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
jiessie:PRIMARY> 
jiessie:PRIMARY> rs.stepDown();
2017-07-22T21:51:26.392+0800 E QUERY    [thread1] Error: error doing query: failed: network error while attempting to run command 'replSetStepDown' on host '127.0.0.1:27017'  :
DB.prototype.runCommand@src/mongo/shell/db.js:132:1
DB.prototype.adminCommand@src/mongo/shell/db.js:150:16
rs.stepDown@src/mongo/shell/utils.js:1261:12
@(shell):1:1
2017-07-22T21:51:26.394+0800 I NETWORK  [thread1] trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2017-07-22T21:51:26.394+0800 I NETWORK  [thread1] reconnect 127.0.0.1:27017 (127.0.0.1) ok
jiessie:SECONDARY> rs.slaveOk();
jiessie:SECONDARY> rs.status();                     #等待几秒，查看状态，此时28017实例是已经提升为新主库
{
        "set" : "jiessie",
        "date" : ISODate("2017-07-22T13:51:34.336Z"),
        "myState" : 2,
        "term" : NumberLong(12),
        "heartbeatIntervalMillis" : NumberLong(2000),
        "optimes" : {
                "lastCommittedOpTime" : {
                        "ts" : Timestamp(1500731480, 1),
                        "t" : NumberLong(12)
                },
                "appliedOpTime" : {
                        "ts" : Timestamp(1500731480, 1),
                        "t" : NumberLong(12)
                },
                "durableOpTime" : {
                        "ts" : Timestamp(1500731480, 1),
                        "t" : NumberLong(12)
                }
        },
        "members" : [
                {
                        "_id" : 0,
                        "name" : "192.168.7.50:27017",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 102106,
                        "optime" : {
                                "ts" : Timestamp(1500731480, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDate" : ISODate("2017-07-22T13:51:20Z"),
                        "infoMessage" : "could not find member to sync from",
                        "configVersion" : 6,
                        "self" : true
                },
                {
                        "_id" : 1,
                        "name" : "192.168.7.50:28017",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 2403,
                        "optime" : {
                                "ts" : Timestamp(1500731480, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDurable" : {
                                "ts" : Timestamp(1500731480, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDate" : ISODate("2017-07-22T13:51:20Z"),
                        "optimeDurableDate" : ISODate("2017-07-22T13:51:20Z"),
                        "lastHeartbeat" : ISODate("2017-07-22T13:51:31.557Z"),
                        "lastHeartbeatRecv" : ISODate("2017-07-22T13:51:33.176Z"),
                        "pingMs" : NumberLong(0),
                        "syncingTo" : "192.168.7.50:29017",
                        "configVersion" : 6
                },
                {
                        "_id" : 2,
                        "name" : "192.168.7.50:29017",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 4846,
                        "optime" : {
                                "ts" : Timestamp(1500731480, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDurable" : {
                                "ts" : Timestamp(1500731480, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDate" : ISODate("2017-07-22T13:51:20Z"),
                        "optimeDurableDate" : ISODate("2017-07-22T13:51:20Z"),
                        "lastHeartbeat" : ISODate("2017-07-22T13:51:31.557Z"),
                        "lastHeartbeatRecv" : ISODate("2017-07-22T13:51:30.019Z"),
                        "pingMs" : NumberLong(0),
                        "configVersion" : 6
                }
        ],
        "ok" : 1
}
jiessie:SECONDARY> exit
bye
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:28017     #登录新主库，原27017实例修改实例引擎
MongoDB shell version v3.4.4
connecting to: localhost:28017
MongoDB server version: 3.4.4
jiessie:PRIMARY> cfg = rs.config();
{
        "_id" : "jiessie",
        "version" : 6,
        "protocolVersion" : NumberLong(1),
        "members" : [
                {
                        "_id" : 0,
                        "host" : "192.168.7.50:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 3,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 1,
                        "host" : "192.168.7.50:28017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 2,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 2,
                        "host" : "192.168.7.50:29017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                }
        ],
        "settings" : {
                "chainingAllowed" : true,
                "heartbeatIntervalMillis" : 2000,
                "heartbeatTimeoutSecs" : 10,
                "electionTimeoutMillis" : 10000,
                "catchUpTimeoutMillis" : 2000,
                "getLastErrorModes" : {

                },
                "getLastErrorDefaults" : {
                        "w" : 1,
                        "wtimeout" : 0
                },
                "replicaSetId" : ObjectId("5971cd4835e57f0331e944c8")
    essie:PRIMARY> cfg.members[0].priority = 0;
0
jiessie:PRIMARY> cfg.members[0].hidden = true;
true
jiessie:PRIMARY> rs.reconfig(cfg);
{ "ok" : 1 }
jiessie:PRIMARY>
修改引擎，删除原数据
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:27017
MongoDB shell version v3.4.4
connecting to: localhost:27017
MongoDB server version: 3.4.4
jiessie:SECONDARY> rs.slaveOk();
jiessie:SECONDARY> use admin;
switched to db admin
jiessie:SECONDARY> db.shutdownServer();                                                      #关闭服务
server should be down...
[root@iZuf6c08fdv8duubho2b0rZ ~]# rm -rf /hwdata/data/mongodb1/data/*                        #删除原引擎数据
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb1/conf/mongodb.conf |grep sto      #查看原配置
storageEngine=mmapv1
[root@iZuf6c08fdv8duubho2b0rZ ~]# sed -i 's@storageEngine=mmapv1@storageEngine=wiredTiger@g' /hwdata/data/mongodb1/conf/mongodb.conf    #修改配置文件的引擎部分
[root@iZuf6c08fdv8duubho2b0rZ ~]# cat /hwdata/data/mongodb2/conf/mongodb.conf |grep sto      #查看新配置
storageEngine=wiredTiger
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongod -f /hwdata/data/mongodb1/conf/mongodb.conf     #启动服务
note: noprealloc may hurt performance in many applications
about to fork child process, waiting until server is ready for connections.
forked process: 2157
child process started successfully, parent exiting
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:27017 --eval "db.serverStatus()"|grep '"name"'    #验证是否修改成功
                "name" : "wiredTiger",
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:27017
MongoDB shell version v3.4.4
connecting to: localhost:27017
MongoDB server version: 3.4.4
jiessie:SECONDARY> exit                     #验证初始化同步是否成功，SECONDARY状态表示已经是从节点
加入副本集
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
[root@iZuf6c08fdv8duubho2b0rZ ~]# /usr/local/mongodb1/bin/mongo localhost:28017
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
jiessie:PRIMARY> cfg = rs.config();
{
        "_id" : "jiessie",
        "version" : 7,
        "protocolVersion" : NumberLong(1),
        "members" : [
                {
                        "_id" : 0,
                        "host" : "192.168.7.50:27017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : true,
                        "priority" : 0,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 1,
                        "host" : "192.168.7.50:28017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 2,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                },
                {
                        "_id" : 2,
                        "host" : "192.168.7.50:29017",
                        "arbiterOnly" : false,
                        "buildIndexes" : true,
                        "hidden" : false,
                        "priority" : 1,
                        "tags" : {

                        },
                        "slaveDelay" : NumberLong(0),
                        "votes" : 1
                }
        ],
        "settings" : {
                "chainingAllowed" : true,
                "heartbeatIntervalMillis" : 2000,
                "heartbeatTimeoutSecs" : 10,
                "electionTimeoutMillis" : 10000,
                "catchUpTimeoutMillis" : 2000,
                "getLastErrorModes" : {

                },
                "getLastErrorDefaults" : {
                        "w" : 1,
                        "wtimeout" : 0
                },
                "replicaSetId" : ObjectId("5971cd4835e57f0331e944c8")
        }
}
jiessie:PRIMARY> cfg.members[0].hidden = false;     #加入副本集，对应用可见，其中[0]表示27017端口
false
jiessie:PRIMARY> cfg.members[0].priority = 3;       #修改为之前的优先级
3
jiessie:PRIMARY> rs.reconfig(cfg);
{ "ok" : 1 }
jiessie:SECONDARY>                                  #等待几秒后，PRIMARY会变成SECONDARY

结束语

mongodb作为发展迅速的开源数据库一员，版本迭代升级很快，目前使用旧引擎的公司不在小数，新引擎的优点足以促使其升级引擎。

-------------本文结束感谢您的阅读-------------