Restore a Sharded Cluster恢复分片群集

Restore the CSRS primary mongod data files.恢复CSRS主mongod数据文件。

Select the tab that corresponds to your preferred backup method:选择与首选备份方法对应的选项卡：

Drop the local database.删除local数据库。

Use db.dropDatabase() to drop the local database:使用db.dropDatabase()删除local数据库：

use local
db.dropDatabase()

For any planned or completed shard hostname or replica set name changes, update the metadata in config.shards .对于任何计划或完成的分片主机名或副本集名称更改，请更新config.shards中的元数据。

You can skip this step if all of the following are true:如果满足以下所有条件，则可以跳过此步骤：

• No shard member host machine hostname has or will change during this procedure.在此过程中，没有或不会更改分片成员主机名。
• No shard replica set name has or will change during this procedure.在此过程中，分片复制集名称没有或将不会更改。

Issue the following find() method on the shards collection in the Config Database. 对配置数据库中的shards集合发出以下find()方法。Replace <shardName> with the name of the shard. 用分片的名称替换<shardName>。By default the shard name is its replica set name. 默认情况下，分片名称是其副本集名称。If you added the shard using the addShard command and specified a custom name, you must specify that name to <shardName>.如果使用addShard命令添加了shard并指定了自定义name，则必须将该名称指定给<shardName>。

use config
db.shards.find( { "_id" : "<shardName>" } )

This operation returns a document that resembles the following:此操作将返回一个类似于以下内容的文档：

{
   "_id" : "shard1",
   "host" : "myShardName/alpha.example.net:27018,beta.example.net:27018,charlie.example.net:27018",
   "state" : 1
}

Use the updateOne() method to update the hosts string to reflect the planned replica set name and hostname list for the shard. 使用updateOne()方法更新hosts字符串，以反映分片的计划副本集名称和主机名列表。For example, the following operation updates the host connection string for the shard with "_id" : "shard1":例如，以下操作会使用"_id" : "shard1"更新分片的host连接字符串：

db.shards.updateOne(
  { "_id" : "shard1" },
  { $set : { "host" : "myNewShardName/repl1.example.net:27018,repl2.example.net:27018,repl3.example.net:27018" } }
)

Repeat this process until all shard metadata accurately reflects the planned replica set name and hostname list for each shard in the cluster.重复此过程，直到所有分片元数据准确反映集群中每个分片的计划副本集名称和主机名列表。

use config
db.shards.find({})

Restart the mongod as a new single-node replica set.作为新的单节点副本集重新启动mongod。

Shut down the mongod. 关闭mongod。Uncomment or add the following configuration file options:取消注释或添加以下配置文件选项：

replication
  replSetName: myNewCSRSName
sharding
  clusterRole: configsvr

If you want to change the replica set name, you must update the replSetName field with the new name before proceeding.如果要更改副本集名称，必须先用新名称更新replSetName字段，然后才能继续。

Start the mongod with the updated configuration file:使用更新的配置文件启动mongod：

mongod --config /path/to/mongodb/mongod.conf

If you have mongod configured to run as a system service, start it using the recommended process for your system service manager.如果已将mongod配置为作为系统服务运行，请使用系统服务管理器建议的流程启动它。

After the mongod starts, connect to it using the mongo shell.mongod启动后，使用mongo shell连接到它。

Initiate the new replica set.启动新的副本集。

Initiate the replica set using rs.initiate() with the default settings.使用带有默认设置的rs.initiate()启动副本集。

rs.initiate()

Once the operation completes, use rs.status() to check that the member has become the primary.操作完成后，使用rs.status()检查成员是否已成为主要成员。

Add additional replica set members.添加其他副本集成员。

For each replica set member in the CSRS, start the mongod on its host machine. 对于CSR中的每个副本集成员，在其主机上启动mongod。Once you have started up all remaining members of the cluster successfully, connect a mongo shell to the primary replica set member. 成功启动集群的所有剩余成员后，将mongo shell连接到主副本集成员。From the primary, use the rs.add() method to add each member of the replica set. 在主副本中，使用rs.add()方法添加副本集的每个成员。Include the replica set name as the prefix, followed by the hostname and port of the member's mongod process:包括副本集名称作为前缀，后跟成员mongod进程的主机名和端口：

rs.add("config2.example.net:27019")
rs.add("config3.example.net:27019")

If you want to add the member with specific replica member configuration settings, you can pass a document to rs.add() that defines the member hostname and any members settings your deployment requires.如果要添加具有特定副本成员配置设置的成员，可以将定义members主机名和部署所需的任何成员设置的文档传递给rs.add()。

rs.add(
 {
   "host" : "config2.example.net:27019",
   priority: <int>,
   votes: <int>,
   tags: <int>
 }
)

Each new member performs an initial sync to catch up to the primary. 每个新成员执行一次初始同步，以赶上主要成员。Depending on factors such as the amount of data to sync, your network topology and health, and the power of each host machine, initial sync may take an extended period of time to complete.根据需要同步的数据量、网络拓扑和运行状况以及每台主机的功率等因素，初始同步可能需要较长的时间才能完成。

The replica set may elect a new primary while you add additional members. 在添加其他成员时，副本集可能会选择一个新的主副本。Use rs.status() to identify which member is the current primary. 使用rs.status()标识哪个成员是当前主成员。You can only run rs.add() from the primary.只能从主服务器运行rs.add()。

Configure any additional required replication settings.配置任何其他必需的复制设置。

The rs.reconfig() method updates the replica set configuration based on a configuration document passed in as a parameter. rs.reconfig()方法根据作为参数传入的配置文档更新副本集配置。You must run reconfig() against the primary member of the replica set.必须对复制集的主要成员运行reconfig()。

Reference the original configuration file output of the replica set as identified in step A. Review Replica Set Configurations and apply settings as needed.参考步骤“A.查看副本集配置并根据需要应用设置”中确定的副本集的原始配置文件输出。

Restore the shard primary mongod data files.还原分片主mongod数据文件。

Select the tab that corresponds to your preferred backup method:选择与首选备份方法对应的选项卡：

Create a temporary user with the __system role.创建具有_系统角色的临时用户。

During this procedure you will modify documents in the admin.system.version collection. 在此过程中，您将修改admin.system.version集合中的文档。For clusters enforcing authentication, only the __system role grants permission to modify this collection. 对于强制验证的集群，只有__system角色授予修改此集合的权限。You can skip this step if the cluster does not enforce authentication.如果集群不强制执行身份验证，则可以跳过此步骤。

1. Authenticate as a user with the userAdmin role on the admin database or userAdminAnyDatabase role:以admin数据库或userAdminAnyDatabase角色上的userAdmin角色的用户身份进行身份验证：

   use admin
   db.auth("myUserAdmin","mySecurePassword")

2. Create a user with the __system role:创建具有__system角色的用户：

   db.createUser(
     {
       user: "mySystemUser",
       pwd: "<replaceMeWithAStrongPassword>",
       roles: [ "__system" ]
     }
   )

   Passwords should be random, long, and complex to ensure system security and to prevent or delay malicious access.密码应该是随机、长且复杂的，以确保系统安全，防止或延迟恶意访问。

3. Authenticate as the privileged user:作为权限用户进行身份验证：

   db.auth("mySystemUser","<replaceMeWithAStrongPassword>")

Drop the local database.删除local数据库。

Use db.dropDatabase() to drop the local database:使用db.dropDatabase()删除local数据库：

use local
db.dropDatabase()

Remove the minOpTimeRecovery document from the admin.system.versions collection.从admin.system.versions集合中删除minOpTimeRecovery文档。

To update the sharding internals, issue the following deleteOne() method on the system.version collection in the admin database:要更新分片内部，请对admin数据库中的system.version集合发出以下deleteOne()方法：

use admin
db.system.version.deleteOne( { _id: "minOpTimeRecovery" } )

Optional: For any CSRS hostname or replica set name changes, update shard metadata in each shard's identity document.每个CSD副本的名称或CSD副本的元数据集的更新都是可选的。

You can skip this step if all of the following are true:如果满足以下所有条件，则可以跳过此步骤：

• The hostnames for any CSRS host did not change during this procedure.在此过程中，任何CSRS主机的主机名都没有更改。
• The CSRS replica set name did not change during this procedure.在此过程中，CSRS副本集名称没有更改。

The system.version collection on the admin database contains metadata related to the shard, including the CSRS connection string. admin数据库上的system.version集合包含与分片相关的元数据，包括CSRS连接字符串。If either the CSRS name or any member hostnames changed while restoring the CSRS, you must update this metadata.如果在恢复CSR时更改了CSRS名称或任何成员主机名，则必须更新此元数据。

Issue the following find() method on the system.version collection in the admin database:对管理数据库中的system.version集合发出以下find()方法：

use admin
db.system.version.find( {"_id" : "shardIdentity" } )

The find() method returns a document that resembles the following:find()方法返回一个类似于以下内容的文档：

{
  "_id" : "shardIdentity",
  "clusterId" : ObjectId("2bba123c6eeedcd192b19024"),
  "shardName" : "shard1",
  "configsvrConnectionString" : "myCSRSName/alpha.example.net:27019,beta.example.net:27019,charlie.example.net:27019" }

The following updateOne() method updates the document such that the host string represents the most current CSRS connection string:以下updateOne()方法更新文档，使host字符串代表最新的CSRS连接字符串：

db.system.version.updateOne(
  { "_id" : "shardIdentity" },
  { $set :
    { "configsvrConnectionString" : "myNewCSRSName/config1.example.net:27019,config2.example.net:27019,config3.example.net:27019"}
  }
)

Restart the mongod as a new single-node replica set.作为新的单节点副本集重新启动mongod。

Shut down the mongod. 关闭mongod。Uncomment or add the following configuration file options:取消注释或添加以下配置文件选项：

replication
  replSetName: myNewShardName
sharding
  clusterRole: shardsvr

If you want to change the replica set name, you must update the replSetName field with the new name before proceeding.如果要更改副本集名称，必须先用新名称更新replSetName字段，然后才能继续。

Start the mongod with the updated configuration file:使用更新的配置文件启动mongod：

mongod --config /path/to/mongodb/mongod.conf

If you have mongod configured to run as a system service, start it using the recommended process for your system service manager.如果已将mongod配置为作为系统服务运行，请使用系统服务管理器建议的流程启动它。

After the mongod starts, connect to it using the mongo shell.mongod启动后，使用mongo shell连接到它。

Initiate the new replica set.启动新的副本集。

Initiate the replica set using rs.initiate() with the default settings.使用带有默认设置的rs.initiate()启动副本集。

rs.initiate()

Once the operation completes, use rs.status() to check that the member has become the primary.操作完成后，使用rs.status()检查成员是否已成为primary。

Add additional replica set members.添加其他副本集成员。

For each replica set member in the shard replica set, start the mongod on its host machine. 对于分片副本集中的每个副本集成员，在其主机上启动mongod。Once you have started up all remaining members of the cluster successfully, connect a mongo shell to the primary replica set member. 成功启动集群的所有剩余成员后，将mongo shell连接到主副本集成员。From the primary, use the rs.add() method to add each member of the replica set. 在主副本中，使用rs.add()方法添加副本集的每个成员。Include the replica set name as the prefix, followed by the hostname and port of the member's mongod process:包括副本集名称作为前缀，后跟成员mongod进程的主机名和端口：

rs.add("repl2.example.net:27018")
rs.add("repl3.example.net:27018")

If you want to add the member with specific replica member configuration settings, you can pass a document to rs.add() that defines the member hostname and any members settings your deployment requires.如果要添加具有特定副本member配置设置的成员，可以将定义成员主机名和部署所需的任何members设置的文档传递给rs.add()。

rs.add(
 {
   "host" : "repl2.example.net:27018",
   priority: <int>,
   votes: <int>,
   tags: <int>
 }
)

Each new member performs an initial sync to catch up to the primary. 每个新成员执行一次初始同步，以赶上主要成员。Depending on factors such as the amount of data to sync, your network topology and health, and the power of each host machine, initial sync may take an extended period of time to complete.根据需要同步的数据量、网络拓扑和运行状况以及每台主机的功率等因素，初始同步可能需要较长的时间才能完成。

The replica set may elect a new primary while you add additional members. 在添加其他成员时，副本集可能会选择一个新的主副本。Use rs.status() to identify which member is the current primary. 使用rs.status()标识哪个成员是当前主成员。You can only run rs.add() from the primary.只能从主服务器运行rs.add()。

Configure any additional required replication settings.配置任何其他必需的复制设置。

The rs.reconfig() method updates the replica set configuration based on a configuration document passed in as a parameter. rs.reconfig()方法根据作为参数传入的配置文档更新副本集配置。You must run reconfig() against the primary member of the replica set.必须对复制集的主要成员运行reconfig()。

Reference the original configuration file output of the replica set as identified in step A. Review Replica Set Configurations and apply settings as needed.参考步骤“A.查看副本集配置并根据需要应用设置”中确定的副本集的原始配置文件输出。

Remove the temporary privileged user.删除临时权限用户。

For clusters enforcing authentication, remove the privileged user created earlier in this procedure:对于强制执行身份验证的群集，请删除在此过程前面创建的权限用户：

1. Authenticate as a user with the userAdmin role on the admin database or userAdminAnyDatabase role:以admin数据库或userAdminAnyDatabase角色上的userAdmin角色的用户身份进行身份验证：

   use admin
   db.auth("myUserAdmin","mySecurePassword")

2. Delete the privileged user:删除权限用户：

   db.removeUser("mySystemUser")