mongodb的备份还原案例
Mongodb自带了mongodump和mongorestore这两个工具来实现对数据的备份和恢复。
mongodump能够在Mongodb运行时进行备份，它的工作原理是对运行的Mongodb做查询，然后将所有查到的文档写入磁盘。但是存在的问题时使用mongodump产生的备份不一定是
数据库的实时快照，如果我们在备份时对数据库进行了写入操作，则备份出来的文件可能不完全和Mongodb实时数据相等。另外在备份时可能会对其它客户端性能产生不利的影响。
mongodump用法；
[root@Mongodb ~]# 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 ( /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)
[root@Mongodb ~]#
参数说明：
-h:指明数据库宿主机的IP
-u:指明数据库的用户名
-p:指明数据库的密码
-d:指明数据库的名字
-c:指明collection的名字
-o:指明到要导出的文件名
-q:指明导出数据的过滤条件
以下是测试用例；
[root@Mongodb db]# mongodump -d test
connected to: 127.0.0.1
Wed Jul 3 00:41:28.975 DATABASE: test to dump/test
Wed Jul 3 00:41:29.024 test.system.indexes to dump/test/system.indexes.bson
Wed Jul 3 00:41:29.031 2 objects
Wed Jul 3 00:41:29.032 test.user to dump/test/user.bson
Wed Jul 3 00:41:29.106 5 objects
Wed Jul 3 00:41:29.107 Metadata for test.user to dump/test/user.metadata.json
Wed Jul 3 00:41:29.114 test.code to dump/test/code.bson
Wed Jul 3 00:41:29.116 28 objects
Wed Jul 3 00:41:29.116 Metadata for test.code to dump/test/code.metadata.json
[root@Mongodb db]#
[root@Mongodb db]# ll
total 164080
-rw------- 1 root root 16777216 Jun 27 23:28 admin.0
-rw------- 1 root root 33554432 Jun 27 23:28 admin.1
-rw------- 1 root root 16777216 Jun 27 23:28 admin.ns
drwxr-xr-x 3 root root 4096 Jul 3 00:41 dump
-rw------- 1 root root 16777216 Jul 3 00:41 local.0
-rw------- 1 root root 16777216 Jul 3 00:41 local.ns
-rwxr-xr-x 1 root root 6 Jul 3 00:41 mongod.lock
-rw------- 1 root root 16777216 Jun 27 22:54 test.0
-rw------- 1 root root 33554432 Jul 1 19:37 test.1
-rw------- 1 root root 16777216 Jun 27 22:54 test.ns
[root@Mongodb db]# cd dump/
You have new mail in /var/spool/mail/root
[root@Mongodb dump]# ls
test
[root@Mongodb dump]# ll
total 8
drwxr-xr-x 2 root root 4096 Jul 3 00:41 test
[root@Mongodb dump]# cd test/
[root@Mongodb test]# ls
code.bson system.indexes.bson user.metadata.json
code.metadata.json user.bson
[root@Mongodb test]# ll
total 40
-rw-r--r-- 1 root root 1036 Jul 3 00:41 code.bson
-rw-r--r-- 1 root root 91 Jul 3 00:41 code.