前几篇文章都是从开发和使用的角度了解了MongoDB的各个知识点，这篇文章将从MongoDB管理的角度入手，了解MongoDB管理所要了解的基本知识。
数据库命令
在前面几篇文章中，已经接触了一些数据库命令，例如文档、索引的操作。
在MongoDB shell中，可以使用runCommand()来传入并执行一个命令文档。例如
> db.runCommand({"getLastError":1})
{ "n" : 0, "connectionId" : 1, "err" : null, "ok" : 1 }
>
MongoDB中的命令其实是作为一种特殊的查询来实现的，这些查询针对$cmd集合来执行。runCommand仅仅是接受命令文档，执行等价的查询操作。所以上面的操作等价于
> db.$cmd.findOne({"getLastError":1})
{ "n" : 0, "connectionId" : 1, "err" : null, "ok" : 1 }
>
但是，“db.$cmd.count()”的结果却总是为0，不知道是不是用户没有权限查看。
通过db.runCommand({"listCommands":1})可以得到MongoDB支持的命令集合。
通过db.help()，可以得到跟数据库相关的命令集合，例如添加删除用户，显示数据库名称，显示所有的collection等等。
> db.help() DB methods: db.addUser(userDocument) db.adminCommand(nameOrDocument) - switches to 'admin' db, and runs command [ just calls db.runCommand(...) ] db.auth(username, password) db.cloneDatabase(fromhost) db.commandHelp(name) returns the help for the command db.copyDatabase(fromdb, todb, fromhost) db.createCollection(name, { size : ..., capped : ..., max : ... } ) db.currentOp() displays currently executing operations in the db db.dropDatabase() db.eval(func, args) run code server-side db.fsyncLock() flush data to disk and lock server for backups db.fsyncUnlock() unlocks server following a db.fsyncLock() db.getCollection(cname) same as db['cname'] or db.cname db.getCollectionNames() ......
服务器状态监控
作为管理员，一定要监控服务器的运行状态。在MongDB中，有三种方式进行服务器状态监控
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MongDB服务器启动时，会一个简单的http服务器，http服务器的端口是MongDB服务器端口加1000.
注：如果启动MongDB服务时，加上"--rest"选项，就可以使用状态监控页面中的链接，查看命令列表，查看副本集状态等等
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在MongoDB shell中，可以通过运行"db.runCommand({"serverStatus ":1})"命令来查看MongoDB服务器的当前状态。
通过serverStatus命令得到的是一个静态结果。结果中的字段含义请参考MongoDB文档。
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在MongoDB的bin文件夹中，有一个"mongostat.exe"程序，通过这个程序可以得到MongoDB服务器的实时状态。
通过"mongostat.exe --help"可以查看它支持的参数选项
C:mongodbin>mongostat.exe --help View live MongoDB performance statistics. usage: mongostat.exe [options] [sleep time] sleep time: time to wait (in seconds) between calls options: --help produce help message -v [ --verbose ] be more verbose (include multiple times for more verbosity e.g. -vvvvv) --version print the program's version and exit -h [ --host ] arg mongo host to connect to ( <set name>/s1,s2 for sets) --port arg server port. Can also use --host hostname:port --ipv6 enable IPv6 support (disabled by default) -u [ --username ] arg username -p [ --password ] arg password --authenticationDatabase arg user source (defaults to dbname) --authenticationMechanism arg (=MONGODB-CR) authentication mechanism --noheaders don't output column names -n [ --rowcount ] arg (=0) number of stats lines to print (0 for indefinite) --http use http instead of raw db connection --discover discover nodes and display stats for all --all all optional fields ......
用户安全认证
在MongoDB中，每个数据库都对应不同的文件，所以可以很方便的管理每个数据库的权限。这里，我们就试试MongoDB的用户安全认证。
首先启动一个MongoDB实例，然后通过MongoDB shell建立两个数据库test1，test2，并且插入一些测试数据，
mongod.exe --dbpath="c:mongodbdbmtest" > use test1 switched to db test1 > for(var i=0;i<10;i++){ ... var randAge = parseInt(5*Math.random()) + 20; ... var gender = (randAge%2)?"Male":"Female"; ... db.student.insert({"sid":i, "name":"Will"+i, "gender": gender, "age": randAge}); ... } > use test2 switched to db test2 > for(var i=0;i<10;i++){ ... var randAge = parseInt(5*Math.random()) + 20; ... var gender = (randAge%2)?"Male":"Female"; ... db.student.insert({"sid":i, "name":"Will"+i, "gender": gender, "age": randAge}); ... } > show dbs local 0.078125GB test1 0.203125GB test2 0.203125GB >
通过下面命令给各个数据库添加用户，其中addUser()的第三个参数表示，是否只有只读权限
use test1 db.addUser("Wilber1", "Wilber1", true) db.addUser("Will1", "Will1") use test2 db.addUser("Wilber2", "Wilber2", true) db.addUser("Will2", "Will2")
接下来，重新启动MongoDB实例，这次需要加上"—auth"选项
mongod.exe --dbpath="c:mongodbdbmtest" –auth
通过下面一系列操作就可以验证上面新添加用户的权限了
C:mongodbin>mongo.exe MongoDB shell version: 2.4.6 connecting to: test > use test1 switched to db test1 > db.student.find() error: { "$err" : "not authorized for query on test1.student", "code" : 16550 } > db.auth("Wilber1","Wilber1") 1 > db.student.find() { "_id" : ObjectId("548d74a241393de780336eb5"), "sid" : 0, "name" : "Will0", "gender" : "Female", "age" : 22 } { "_id" : ObjectId("548d74a241393de780336eb6"), "sid" : 1, "name" : "Will1", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d74a241393de780336eb7"), "sid" : 2, "name" : "Will2", "gender" : "Male", "age" : 23 } { "_id" : ObjectId("548d74a241393de780336eb8"), "sid" : 3, "name" : "Will3", "gender" : "Female", "age" : 20 } { "_id" : ObjectId("548d74a241393de780336eb9"), "sid" : 4, "name" : "Will4", "gender" : "Female", "age" : 20 } { "_id" : ObjectId("548d74a241393de780336eba"), "sid" : 5, "name" : "Will5", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d74a241393de780336ebb"), "sid" : 6, "name" : "Will6", "gender" : "Male", "age" : 23 } { "_id" : ObjectId("548d74a241393de780336ebc"), "sid" : 7, "name" : "Will7", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d74a241393de780336ebd"), "sid" : 8, "name" : "Will8", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d74a241393de780336ebe"), "sid" : 9, "name" : "Will9", "gender" : "Male", "age" : 21 } > db.student.insert({"name":"July"}) not authorized for insert on test1.student > db.auth("Will1","Will1") 1 > db.student.insert({"name":"July"}) > db.auth("Will2","Will2") Error: 18 { code: 18, ok: 0.0, errmsg: "auth fails" } 0 > use test2 switched to db test2 > db.student.find() error: { "$err" : "not authorized for query on test2.student", "code" : 16550 } >
上面只是给各个数据库添加用户，我们也可以给这个MongoDB实例添加一个管理员。这个管理员对所有的数据库都有读写权限，并且可以管理各个数据库的用户。
use admin db.addUser("root","root") db.auth("root","root")
数据库备份与恢复
在数据库的使用过程中，会经常遇到需要备份、恢复数据库的情况。在MongoDB中，我们使用"mongodump.exe"和"mongorestore.exe"来分别完成MongoDB的备份和恢复工作。
通过"--help"来查看mongodump支持的参数
C:mongodbin>mongodump --help Export MongoDB data to BSON files. options: --help produce help message -v [ --verbose ] be more verbose (include multiple times for more verbosity e.g. -vvvvv) --version print the program's version and exit -h [ --host ] arg mongo host to connect to ( <set name>/s1,s2 for sets) --port arg server port. Can also use --host hostname:port --ipv6 enable IPv6 support (disabled by default) -u [ --username ] arg username -p [ --password ] arg password --authenticationDatabase arg user source (defaults to dbname) --authenticationMechanism arg (=MONGODB-CR) authentication mechanism --dbpath arg directly access mongod database files in the given path, instead of connecting to a mongod server - needs to lock the data directory, so cannot be used if a mongod is currently accessing the same path --directoryperdb each db is in a separate directly (relevant only if dbpath specified) --journal enable journaling (relevant only if dbpath specified) -d [ --db ] arg database to use -c [ --collection ] arg collection to use (some commands) -o [ --out ] arg (=dump) output directory or "-" for stdout -q [ --query ] arg json query --oplog Use oplog for point-in-time snapshotting --repair try to recover a crashed database --forceTableScan force a table scan (do not use $snapshot)
进入实验，通过mongodump来备份test1数据库到"C:mongodbdbackup"文件夹，由于我们前面设置了test1的访问权限，所以要加入用户登录信息进行数据库备份。实验中发现，当使用只读用户（Wilber1）进行数据库备份的时候，会遇到权限错误。
C:mongodbin>mongodump -u Will1 -p Will1 -d test1 -o "c:mongodbdbackup" connected to: 127.0.0.1 Sun Dec 14 20:11:54.442 DATABASE: test1 to c:mongodbdbackup est1 Sun Dec 14 20:11:54.444 test1.system.indexes to c:mongodbdbackup est1system.indexes.bson Sun Dec 14 20:11:54.446 3 objects Sun Dec 14 20:11:54.448 test1.student to c:mongodbdbackup est1student.bson Sun Dec 14 20:11:54.450 11 objects Sun Dec 14 20:11:54.451 Metadata for test1.student to c:mongodbdbackup est1student.metadata.json Sun Dec 14 20:11:54.456 test1.system.users to c:mongodbdbackup est1system.users.bson Sun Dec 14 20:11:54.458 2 objects Sun Dec 14 20:11:54.459 Metadata for test1.system.users to c:mongodbdbackup est1system.users.metadata.json
下面来进行数据库恢复，首先通过MongoDB shell把test1中的student表删除，然后恢复
> db.student.drop() true > show collections system.indexes system.users
C:mongodbin>mongorestore -u Will1 -p Will1 -d test1 --drop "c:mongodbdbackup est1" connected to: 127.0.0.1 Sun Dec 14 20:29:52.285 c:mongodbdbackup est1student.bson Sun Dec 14 20:29:52.287 going into namespace [test1.student] Sun Dec 14 20:29:52.287 dropping 11 objects found Sun Dec 14 20:29:52.293 Creating index: { key: { _id: 1 }, ns: "test1.student", name: "_id_" } Sun Dec 14 20:29:52.296 c:mongodbdbackup est1system.users.bson Sun Dec 14 20:29:52.296 going into namespace [test1.system.users] 2 objects found Sun Dec 14 20:29:52.300 Creating index: { key: { _id: 1 }, ns: "test1.system.users", name: "_id_" } Sun Dec 14 20:29:52.302 Creating index: { key: { user: 1, userSource: 1 }, unique: true, ns: "test1.system.users", name: "user_1_use rSource_1" }
> show collections system.indexes system.users > show collections student system.indexes system.users > db.student.find() { "_id" : ObjectId("548d74a241393de780336eb5"), "sid" : 0, "name" : "Will0", "gender" : "Female", "age" : 22 } { "_id" : ObjectId("548d74a241393de780336eb6"), "sid" : 1, "name" : "Will1", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d74a241393de780336eb7"), "sid" : 2, "name" : "Will2", "gender" : "Male", "age" : 23 } { "_id" : ObjectId("548d74a241393de780336eb8"), "sid" : 3, "name" : "Will3", "gender" : "Female", "age" : 20 } { "_id" : ObjectId("548d74a241393de780336eb9"), "sid" : 4, "name" : "Will4", "gender" : "Female", "age" : 20 } { "_id" : ObjectId("548d74a241393de780336eba"), "sid" : 5, "name" : "Will5", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d74a241393de780336ebb"), "sid" : 6, "name" : "Will6", "gender" : "Male", "age" : 23 } { "_id" : ObjectId("548d74a241393de780336ebc"), "sid" : 7, "name" : "Will7", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d74a241393de780336ebd"), "sid" : 8, "name" : "Will8", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d74a241393de780336ebe"), "sid" : 9, "name" : "Will9", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d77b0e71a5046dd2ab620"), "name" : "July" } >
关于fsync
mongodump和mongorestore比较好的是，它们可以支持在不停止数据库服务的情况下进行数据库的备份和恢复。但是，如果数据库在备份的过程中有新的数据插入数据库，或者缓存中的数据还没有及时的写入硬盘，则通过mongodump备份得到的数据可能已经不是最新的了。
为了解决这个问题，我们可以使用fsync。fsync命令会强制服务器将所有的缓冲区数据写入内存，这时我们还可以选择上锁来阻止对数据库的写操作，知道锁释放为止。
为了方便实验，重新启动MongoDB实例，去掉"--auth"选项。打开两个MongoDB shell，下面分别称为shell1和shell2。
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在shell1中使用fsync来加上写锁
> use admin switched to db admin > db.runCommand({"fsync":1,"lock":1}) { "info" : "now locked against writes, use db.fsyncUnlock() to unlock", "seeAlso" : "http://dochub.mongodb.org/core/fsynccommand", "ok" : 1 }
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在shell2中使用以下命令输入数据，可以看到下面的写操作会一直被阻塞
> use test1 switched to db test1 > for(var i=0;i<10;i++){ ... var randAge = parseInt(5*Math.random()) + 20; ... var gender = (randAge%2)?"Male":"Female"; ... db.student.insert({"sid":i, "name":"Will"+i, "gender": gender, "age": randAge}); ... }
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回到shell1，使用下面命令解锁
> db.fsyncUnlock() { "ok" : 1, "info" : "unlock completed" }
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这时，可以看到哦shell2中已经有响应了，通过find查询数据，看到会面需要加入的数据已经进入test1数据库了
> db.student.find() { "_id" : ObjectId("548d74a241393de780336eb5"), "sid" : 0, "name" : "Will0", "gender" : "Female", "age" : 22 } { "_id" : ObjectId("548d74a241393de780336eb6"), "sid" : 1, "name" : "Will1", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d74a241393de780336eb7"), "sid" : 2, "name" : "Will2", "gender" : "Male", "age" : 23 } { "_id" : ObjectId("548d74a241393de780336eb8"), "sid" : 3, "name" : "Will3", "gender" : "Female", "age" : 20 } { "_id" : ObjectId("548d74a241393de780336eb9"), "sid" : 4, "name" : "Will4", "gender" : "Female", "age" : 20 } { "_id" : ObjectId("548d74a241393de780336eba"), "sid" : 5, "name" : "Will5", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d74a241393de780336ebb"), "sid" : 6, "name" : "Will6", "gender" : "Male", "age" : 23 } { "_id" : ObjectId("548d74a241393de780336ebc"), "sid" : 7, "name" : "Will7", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d74a241393de780336ebd"), "sid" : 8, "name" : "Will8", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d74a241393de780336ebe"), "sid" : 9, "name" : "Will9", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d77b0e71a5046dd2ab620"), "name" : "July" } { "_id" : ObjectId("548d856947119de938024cda"), "sid" : 0, "name" : "Will0", "gender" : "Male", "age" : 23 } { "_id" : ObjectId("548d856947119de938024cdb"), "sid" : 1, "name" : "Will1", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d856947119de938024cdc"), "sid" : 2, "name" : "Will2", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d856947119de938024cdd"), "sid" : 3, "name" : "Will3", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d856947119de938024cde"), "sid" : 4, "name" : "Will4", "gender" : "Female", "age" : 24 } { "_id" : ObjectId("548d856947119de938024cdf"), "sid" : 5, "name" : "Will5", "gender" : "Female", "age" : 22 } { "_id" : ObjectId("548d856947119de938024ce0"), "sid" : 6, "name" : "Will6", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d856947119de938024ce1"), "sid" : 7, "name" : "Will7", "gender" : "Male", "age" : 21 } { "_id" : ObjectId("548d856947119de938024ce2"), "sid" : 8, "name" : "Will8", "gender" : "Male", "age" : 23 } Type "it" for more > it { "_id" : ObjectId("548d856947119de938024ce3"), "sid" : 9, "name" : "Will9", "gender" : "Female", "age" : 20 } >
以服务的方式运行MongoDB
MongoDB支持以Windows service的方式运行，这样我们就没有必要每次都通过mongod来启动MongoDB实例了。
使用下面命令来新建一个MongoDB服务
C:mongodbin>mongod.exe --dbpath="c:mongodbdbmtest" --logpath="c:mongodbdbmtestmtestLog.txt" --install --serviceName="MyMongo" --s erviceDisplayName="MyMongoService" Sun Dec 14 20:59:31.402 Trying to install Windows service 'MyMongo' Sun Dec 14 20:59:31.449 Service 'MyMongo' (MyMongoService) installed with command line 'C:mongodbinmongod.exe --dbpath=c:mongodbdbmte st --logpath=c:mongodbdbmtestmtestLog.txt --service' Sun Dec 14 20:59:31.449 Service can be started from the command line with 'net start MyMongo'
参数的含义：
- --logpath：MongoDB运行中的log保存路径。通过mongod启动服务的时候，所有的log都是直接在控制台窗口打印的。
- --install：安装Windows service
- --serviceName：安装的service的名称，我们可以通过这个名字的启动MongoDB服务，'net start MyMongo'
- --erviceDisplayName：service在Windows service列表中显示的名字
查看Windows service列表，可以看到已经安装的服务
接下来通过MongoDB shell来启动刚安装的service
C:mongodbin>net start MyMongo The MyMongoService service was started successfully. C:mongodbin>mongo.exe MongoDB shell version: 2.4.6 connecting to: test > use test1 switched to db test1 > db.student.count() 21 >
通过"net stop MyMongo"可以关闭service。
另外，通过"--remove"选项可以移除MongoDB service
C:mongodbin>mongod.exe --remove --serviceName=MyMongo Sun Dec 14 21:12:28.202 Trying to remove Windows service 'MyMongo' Sun Dec 14 21:12:28.202 Service 'MyMongo' removed
总结
本篇文章主要介绍了MongDB管理中需要用到的基本知识。
Ps：例子中所有的命令都可以参考以下链接
http://files.cnblogs.com/wilber2013/management.js