使用 PowerShell 和 Azure 数据库迁移服务将 MySQL 脱机迁移到 Azure Database for MySQL

项目
01/19/2024

本文介绍如何通过 Azure PowerShell 使用 Azure 数据库迁移服务的脱机迁移功能，将还原到本地实例的 MySQL 数据库迁移到 Azure Database for MySQL。本文介绍 PowerShell 脚本的集合，按顺序执行这些脚本可以将 MySQL 数据库脱机迁移到 Azure。你可以从 GitHub 存储库下载本教程中所述的完整 PowerShell 脚本。

注意

目前不能使用 Az.DataMigration 模块运行完整的数据库迁移。同时，示例 PowerShell 脚本“按原样”提供，该脚本使用 DMS REST API，并允许自动执行迁移。当 Az.DataMigration 模块和 Azure CLI 中添加正式支持后，此脚本将被修改或弃用。

注意

另外，支持 Amazon Relational Database Service (RDS) for MySQL 和 Amazon Aurora（基于 MySQL）作为源进行迁移。

重要

对于联机迁移，可以将 MyDumper/MyLoader 之类的开源工具与数据传入复制配合使用。

本文有助于自动处理以下场景：源数据库名称和目标数据库名称可以相同或不同，以及在迁移过程中，需要迁移目标数据库中具有相同名称和表结构的所有表或部分表。虽然本文假设源为 MySQL 数据库实例，目标为 Azure Database for MySQL，但只需更改源服务器名称和凭据，本文即可用于在 Azure Database for MySQL 之间迁移。此外，还支持从低版本的 MySQL 服务器（5.6 和更高版本）迁移到高版本。

重要

DMS 预览功能是可选择启用的自助功能。预览版是“按原样”和“按可用”提供的，并且未包含在服务级别协议和有限保修中。因此，这些功能并不适合用于生产。

在本文中，学习如何：

迁移数据库架构。
创建资源组。
创建 Azure 数据库迁移服务的实例。
在 Azure 数据库迁移服务实例中创建迁移项目。
将迁移项目配置为使用 MySQL 的脱机迁移功能。
运行迁移。

先决条件

若要完成这些步骤，需满足以下条件：

具有活动订阅的 Azure 帐户。创建试用帐户。
具有 5.6 或更高版本的本地 MySQL 数据库。如果没有，请下载并安装 MySQL 社区版 5.6 或更高版本。
在 Azure Database for MySQL 中创建一个实例。有关如何使用 Workbench 应用程序连接和创建数据库的详细信息，请参阅使用 MySQL Workbench 进行连接并查询数据一文。 Azure Database for MySQL 的版本应不低于本地 MySQL 版本。例如，MySQL 5.7 可以迁移到 Azure Database for MySQL 5.7，或升级到 8。
使用 Azure 资源管理器部署模型创建 Azure 数据库迁移服务的 Azure 虚拟网络，该网络将使用 ExpressRoute 或 VPN 提供与本地源服务器的站点到站点连接。有关创建虚拟网络的详细信息，请参阅虚拟网络文档，尤其是提供了分步详细信息的快速入门文章。

注意

在虚拟网络 (VNet) 设置期间，如果将 ExpressRoute 与 Microsoft 的网络对等互连一起使用，则请将 Microsoft.Sql 服务终结点添加到要在其中预配该服务的子网。 Azure 数据库迁移服务缺少 Internet 连接，因此必须提供此配置。
请确保虚拟网络的网络安全组规则不阻止存储服务和 AzureMonitor 的 ServiceTag 出站端口 443。有关虚拟网络 NSG 流量筛选的更多详细信息，请参阅使用网络安全组筛选网络流量一文。
打开 Windows 防火墙，使 Azure 数据库迁移服务的虚拟网络发出的连接能够访问源 MySQL 服务器（默认情况下为 TCP 端口 3306）。
在源数据库的前面使用了防火墙设备时，可能需要添加防火墙规则以允许 Azure 数据库迁移服务的虚拟网络发出的连接访问要迁移的源数据库。
为目标 Azure Database for MySQL 创建服务器级别的防火墙规则或配置 VNET 服务器终结点，以允许 Azure 数据迁移服务的虚拟机网络访问目标数据库。
源 MySQL 必须使用支持的 MySQL 社区版。若要确定 MySQL 实例的版本，请在 MySQL 实用程序或 MySQL Workbench 中运行以下命令：
```
SELECT @@version;
```
Azure Database for MySQL 仅支持 InnoDB 表。若要将 MyISAM 表转换为 InnoDB，请参阅 Converting Tables from MyISAM to InnoDB（将表从 MyISAM 转换为 InnoDB）一文
用户必须具有读取源数据库上数据的权限。
本指南使用 PowerShell v7.2，可以按照安装指南将其安装
使用 Install-Module PowerShell cmdlet 从 PowerShell 库下载并安装以下模块；请务必使用“以管理员身份运行”来打开 PowerShell 命令窗口：
- Az.Resources
- Az.Network
- Az.DataMigration

Install-Module Az.Resources
Install-Module Az.Network
Install-Module Az.DataMigration
Import-Module Az.Resources
Import-Module Az.Network
Import-Module Az.DataMigration

迁移数据库架构

要传输所有数据库对象（例如表架构、索引和存储过程），需从源数据库提取架构并将其应用到目标数据库。若要提取架构，可以将 mysqldump 与 --no-data 参数配合使用。为此，需要一台可以连接到源 MySQL 数据库和目标 Azure Database for MySQL 的计算机。

要使用 mysqldump 导出架构，请运行以下命令：

mysqldump -h [servername] -u [username] -p[password] --databases [db name] --no-data > [schema file path]

例如：

mysqldump -h 10.10.123.123 -u root -p --databases migtestdb --no-data > d:\migtestdb.sql

要将架构导入到目标 Azure Database for MySQL，请运行以下命令：

mysql.exe -h [servername] -u [username] -p[password] [database]< [schema file path]

例如：

mysql.exe -h mysqlsstrgt.mysql.database.chinacloudapi.cn -u docadmin@mysqlsstrgt -p migtestdb < d:\migtestdb.sql

如果在架构中有外键，则迁移任务将处理迁移过程中的并行数据加载。在架构迁移期间不需要删除外键。

如果数据库中有触发器，它将在从源进行完整数据迁移之前在目标中强制实施数据完整性。建议在迁移期间禁用目标中所有表的触发器，然后在迁移完成后再启用这些触发器。

在 MySQL Workbench 中对目标数据库执行以下脚本，以提取“删除触发器”脚本和“添加触发器”脚本。

SELECT
    SchemaName,
    GROUP_CONCAT(DropQuery SEPARATOR ';\n') as DropQuery,
    Concat('DELIMITER $$ \n\n', GROUP_CONCAT(AddQuery SEPARATOR '$$\n'), '$$\n\nDELIMITER ;') as AddQuery
FROM
(
SELECT
    TRIGGER_SCHEMA as SchemaName,
    Concat('DROP TRIGGER `', TRIGGER_NAME, "`") as DropQuery,
    Concat('CREATE TRIGGER `', TRIGGER_NAME, '` ', ACTION_TIMING, ' ', EVENT_MANIPULATION,
            '\nON `', EVENT_OBJECT_TABLE, '`\n' , 'FOR EACH ', ACTION_ORIENTATION, ' ',
            ACTION_STATEMENT) as AddQuery
FROM
    INFORMATION_SCHEMA.TRIGGERS
ORDER BY EVENT_OBJECT_SCHEMA, EVENT_OBJECT_TABLE, ACTION_TIMING, EVENT_MANIPULATION, ACTION_ORDER ASC
) AS Queries
GROUP BY SchemaName

在结果中运行生成的“删除触发器”查询（DropQuery 列），以删除目标数据库中的触发器。可保存“添加触发器”查询，以供数据迁移完成后使用。

登录到 Azure 订阅

按照使用 Azure PowerShell 登录一文中的说明，在 PowerShell 中使用 Connect-AzAccount PowerShell 命令登录到你的 Azure 订阅。

以下脚本为 PowerShell 会话登录后设置默认订阅，并为格式化的控制台日志创建帮助程序日志记录函数。

[string] $SubscriptionName = "mySubscription"
$ErrorActionPreference = "Stop";

Connect-AzAccount -Environment AzureChinaCloud
Set-AzContext -Subscription $SubscriptionName
$global:currentSubscriptionId = (Get-AzContext).Subscription.Id;

function LogMessage([string] $Message, [bool] $IsProcessing = $false) {
    if ($IsProcessing) {
        Write-Host "$(Get-Date -Format "yyyy-MM-dd HH:mm:ss"): $Message" -ForegroundColor Yellow
    }
    else {
        Write-Host "$(Get-Date -Format "yyyy-MM-dd HH:mm:ss"): $Message" -ForegroundColor Green
    }
}

注册 Microsoft.DataMigration 资源提供程序

每个 Azure 订阅只需注册一次资源提供程序。如果没有注册，你将无法创建 Azure 数据库迁移服务的实例。

使用 Register-AzResourceProvider 命令注册资源提供程序。以下脚本注册 Azure 数据库迁移服务所需的资源提供程序

Register-AzResourceProvider -ProviderNamespace Microsoft.DataMigration

创建资源组

Azure 资源组是在其中部署和管理 Azure 资源的逻辑容器。请先创建一个资源组，然后再创建任何 DMS 资源。

使用 New-AzResourceGroup 命令创建资源组。

以下示例在中国东部 2 区域的默认订阅 mySubscription 下创建了一个名为 myResourceGroup 的资源组。

# Get the details of resource group
[string] $Location = "chinaeast2"
[string] $ResourceGroupName = "myResourceGroup"

$resourceGroup = Get-AzResourceGroup -Name $ResourceGroupName
if (-not($resourceGroup)) {
    LogMessage -Message "Creating resource group $ResourceGroupName..." -IsProcessing $true
    $resourceGroup = New-AzResourceGroup -Name $ResourceGroupName -Location $Location
    LogMessage -Message "Created resource group - $($resourceGroup.ResourceId)."
}
else { LogMessage -Message "Resource group $ResourceGroupName exists." }

创建 Azure 数据库迁移服务的实例

可以通过使用 New-AzDataMigrationService 命令创建 Azure 数据库迁移服务的新实例。此命令需要以下必需参数：

Azure 资源组名称。可以使用 New-AzResourceGroup 命令创建前述 Azure 资源组，并提供其名称作为参数。
服务名称。与 Azure 数据库迁移服务的所需唯一服务名称相对应的字符串
位置。指定服务的位置。指定 Azure 数据中心位置，例如“中国东部”
Sku。此参数对应于 DMS Sku 名称。当前支持的 Sku 名称为 Standard_1vCore、Standard_2vCores、Standard_4vCores、Premium_4vCores 。
虚拟子网标识符。可以使用 Get-AzVirtualNetworkSubnetConfig 命令获取子网的信息。

以下脚本要求存在一个子网名为 default 的 myVirtualNetwork 虚拟网络，然后在同一区域中，在步骤 3 创建的资源组下，创建名为 myDmService 的数据库迁移服务。

# Get a reference to the DMS service - Create if not exists
[string] $VirtualNetworkName = "myVirtualNetwork"
[string] $SubnetName = "default"
[string] $ServiceName = "myDmService"

$dmsServiceResourceId = "/subscriptions/$($global:currentSubscriptionId)/resourceGroups/$ResourceGroupName/providers/Microsoft.DataMigration/services/$ServiceName"
$dmsService = Get-AzResource -ResourceId $dmsServiceResourceId -ErrorAction SilentlyContinue

# Create Azure DMS service if not existing
# Possible values for SKU currently are Standard_1vCore,Standard_2vCores,Standard_4vCores,Premium_4vCores
if (-not($dmsService)) {
    $virtualNetwork = Get-AzVirtualNetwork -ResourceGroupName $ResourceGroupName -Name $VirtualNetworkName
    if (-not ($virtualNetwork)) { throw "ERROR: Virtual Network $VirtualNetworkName does not exists" }

    $subnet = Get-AzVirtualNetworkSubnetConfig -VirtualNetwork $virtualNetwork -Name $SubnetName
    if (-not ($subnet)) { throw "ERROR: Virtual Network $VirtualNetworkName does not contains Subnet $SubnetName" }

    LogMessage -Message "Creating Azure Data Migration Service $ServiceName..." -IsProcessing $true
    $dmsService = New-AzDataMigrationService `
        -ResourceGroupName $ResourceGroupName `
        -Name $ServiceName `
        -Location $resourceGroup.Location `
        -Sku Premium_4vCores `
        -VirtualSubnetId $Subnet.Id

    $dmsService = Get-AzResource -ResourceId $dmsServiceResourceId
    LogMessage -Message "Created Azure Data Migration Service - $($dmsService.ResourceId)."
}
else { LogMessage -Message "Azure Data Migration Service $ServiceName exists." }

创建迁移项目

在创建 Azure 数据库迁移服务实例以后，将创建迁移项目。迁移项目指定需要执行的迁移类型。

以下脚本在同一区域中，在步骤 4 创建的数据迁移服务实例下，创建一个名为 myfirstmysqlofflineproject 的迁移项目，用于从 MySQL 脱机迁移到 Azure Database for MySQL。

# Get a reference to the DMS project - Create if not exists
[string] $ProjectName = "myfirstmysqlofflineproject"

$dmsProjectResourceId = "/subscriptions/$($global:currentSubscriptionId)/resourceGroups/$($dmsService.ResourceGroupName)/providers/Microsoft.DataMigration/services/$($dmsService.Name)/projects/$projectName"
$dmsProject = Get-AzResource -ResourceId $dmsProjectResourceId -ErrorAction SilentlyContinue

# Create Azure DMS Project if not existing
if (-not($dmsProject)) {
    LogMessage -Message "Creating Azure DMS project $projectName for MySQL migration ..." -IsProcessing $true

    $newProjectProperties = @{"sourcePlatform" = "MySQL"; "targetPlatform" = "AzureDbForMySQL" }
    $dmsProject = New-AzResource `
        -ApiVersion 2018-03-31-preview `
        -Location $dmsService.Location `
        -ResourceId $dmsProjectResourceId `
        -Properties $newProjectProperties `
        -Force

    LogMessage -Message "Created Azure DMS project $projectName - $($dmsProject.ResourceId)."
}
else { LogMessage -Message "Azure DMS project $projectName exists." }

创建源和目标连接的数据库连接信息对象

创建迁移项目后，将创建数据库连接信息。此连接信息将在迁移过程中用于连接到源服务器和目标服务器。

以下脚本获取源和目标 MySQL 实例的服务器名称、用户名和密码，并创建连接信息对象。该脚本会提示用户输入源和目标 MySQL 实例的密码。对于无提示脚本，可以从 Azure Key Vault 提取凭据。

# Initialize the source and target database server connections
[string] $SourceServerName = "13.66.136.192"
[string] $SourceUserName = "docadmin@mysqlserver"
[securestring] $SourcePassword = Read-Host "Enter MySQL Source Server Password" -AsSecureString

[string] $TargetServerName = "migdocdevwus2mysqlsstrgt.mysql.database.chinacloudapi.cn"
[string] $TargetUserName = "docadmin@migdocdevwus2mysqlsstrgt"
[securestring] $TargetPassword = Read-Host "Enter MySQL Target Server Password" -AsSecureString

function InitConnection(
    [string] $ServerName,
    [string] $UserName,
    [securestring] $Password) {
    $connectionInfo = @{
        "dataSource"             = "";
        "serverName"             = "";
        "port"                   = 3306;
        "userName"               = "";
        "password"               = "";
        "authentication"         = "SqlAuthentication";
        "encryptConnection"      = $true;
        "trustServerCertificate" = $true;
        "additionalSettings"     = "";
        "type"                   = "MySqlConnectionInfo"
    }

    $connectionInfo.dataSource = $ServerName;
    $connectionInfo.serverName = $ServerName;
    $connectionInfo.userName = $UserName;
    $connectionInfo.password = (ConvertFrom-SecureString -AsPlainText $password).ToString();
    $connectionInfo;
}

# Initialize the source and target connections
LogMessage -Message "Initializing source and target connection objects ..." -IsProcessing $true
$sourceConnInfo = InitConnection `
    $SourceServerName `
    $SourceUserName `
    $SourcePassword;

$targetConnInfo = InitConnection `
    $TargetServerName `
    $TargetUserName `
    $TargetPassword;

LogMessage -Message "Source and target connection object initialization complete."

从目标数据库中提取表名称的列表

可以使用迁移任务和连接信息提取数据库表列表。表列表将从源数据库和目标数据库中提取，以便能够进行正确的映射和验证。

以下脚本获取源数据库和目标数据库的名称，然后通过 GetUserTablesMySql 迁移任务从数据库中提取表列表。

# Run scenario to get the tables from the target database to build
# the migration table mapping
[string] $TargetDatabaseName = "migtargetdb"
[string] $SourceDatabaseName = "migsourcedb"

function RunScenario([object] $MigrationService,
    [object] $MigrationProject,
    [string] $ScenarioTaskName,
    [object] $TaskProperties,
    [bool] $WaitForScenario = $true) {
    # Check if the scenario task already exists, if so remove it
    LogMessage -Message "Removing scenario if already exists..." -IsProcessing $true
    Remove-AzDataMigrationTask `
        -ResourceGroupName $MigrationService.ResourceGroupName `
        -ServiceName $MigrationService.Name `
        -ProjectName $MigrationProject.Name `
        -TaskName $ScenarioTaskName `
        -Force;

    # Start the new scenario task using the provided properties
    LogMessage -Message "Initializing scenario..." -IsProcessing $true
    New-AzResource `
        -ApiVersion 2018-03-31-preview `
        -Location $MigrationService.Location `
        -ResourceId "/subscriptions/$($global:currentSubscriptionId)/resourceGroups/$($MigrationService.ResourceGroupName)/providers/Microsoft.DataMigration/services/$($MigrationService.Name)/projects/$($MigrationProject.Name)/tasks/$($ScenarioTaskName)" `
        -Properties $TaskProperties `
        -Force | Out-Null;

    LogMessage -Message "Waiting for $ScenarioTaskName scenario to complete..." -IsProcessing $true
    if ($WaitForScenario) {
        $progressCounter = 0;
        do {
            if ($null -ne $scenarioTask) {
                Start-Sleep 10;
            }

            # Get calls can time out and will return a cancellation exception in that case
            $scenarioTask = Get-AzDataMigrationTask `
                -ResourceGroupName $MigrationService.ResourceGroupName `
                -ServiceName $MigrationService.Name `
                -ProjectName $MigrationProject.Name `
                -TaskName $ScenarioTaskName `
                -Expand `
                -ErrorAction Ignore;

            Write-Progress -Activity "Scenario Run $ScenarioTaskName  (Marquee Progress Bar)" `
                -Status $scenarioTask.ProjectTask.Properties.State `
                -PercentComplete $progressCounter

            $progressCounter += 10;
            if ($progressCounter -gt 100) { $progressCounter = 10 }
        }
        while (($null -eq $scenarioTask) -or ($scenarioTask.ProjectTask.Properties.State -eq "Running") -or ($scenarioTask.ProjectTask.Properties.State -eq "Queued"))
    }
    Write-Progress -Activity "Scenario Run $ScenarioTaskName" `
        -Status $scenarioTask.ProjectTask.Properties.State `
        -Completed

    # Now get it using REST APIs so we can expand the output
    LogMessage -Message "Getting expanded task results ..." -IsProcessing $true
    $psToken = (Get-AzAccessToken -ResourceUrl https://management.chinacloudapi.cn).Token;
    $token = ConvertTo-SecureString -String $psToken -AsPlainText -Force;
    $taskResource = Invoke-RestMethod `
        -Method GET `
        -Uri "https://management.chinacloudapi.cn$($scenarioTask.ProjectTask.Id)?api-version=2018-03-31-preview&`$expand=output" `
        -ContentType "application/json" `
        -Authentication Bearer `
        -Token $token;

    $taskResource.properties;
}

# create the get table task properties by initializing the connection and
# database name
$getTablesTaskProperties = @{
    "input"    = @{
        "connectionInfo"    = $null;
        "selectedDatabases" = $null;
    };
    "taskType" = "GetUserTablesMySql";
};

LogMessage -Message "Running scenario to get the list of tables from the target database..." -IsProcessing $true
$getTablesTaskProperties.input.connectionInfo = $targetConnInfo;
$getTablesTaskProperties.input.selectedDatabases = @($TargetDatabaseName);
# Create a name for the task
$getTableTaskName = "$($TargetDatabaseName)GetUserTables"
# Get the list of tables from the source
$getTargetTablesTask = RunScenario -MigrationService $dmsService `
    -MigrationProject $dmsProject `
    -ScenarioTaskName $getTableTaskName `
    -TaskProperties $getTablesTaskProperties;

if (-not ($getTargetTablesTask)) { throw "ERROR: Could not get target database $TargetDatabaseName table information." }
LogMessage -Message "List of tables from the target database acquired."

LogMessage -Message "Running scenario to get the list of tables from the source database..." -IsProcessing $true
$getTablesTaskProperties.input.connectionInfo = $sourceConnInfo;
$getTablesTaskProperties.input.selectedDatabases = @($SourceDatabaseName);
# Create a name for the task
$getTableTaskName = "$($SourceDatabaseName)GetUserTables"
# Get the list of tables from the source
$getSourceTablesTask = RunScenario -MigrationService $dmsService `
    -MigrationProject $dmsProject `
    -ScenarioTaskName $getTableTaskName `
    -TaskProperties $getTablesTaskProperties;

if (-not ($getSourceTablesTask)) { throw "ERROR: Could not get source database $SourceDatabaseName table information." }
LogMessage -Message "List of tables from the source database acquired."

基于用户配置生成表映射

在配置迁移任务的过程中，将创建源表和目标表之间的映射。虽然映射处于表名称级别，但我们假设被映射表的表结构（列计数、列名称、数据类型等）完全相同。

以下脚本基于步骤 7 中提取的目标和源表列表创建映射。如果是部分数据加载，用户可以提供表列表以筛选掉这些表。如果未提供用户输入，则映射所有目标表。该脚本还会检查源中是否存在具有相同名称的表。如果源中不存在表名，则在迁移时会忽略目标表。

# Create the source to target table map
# Optional table settings
# DEFAULT: $IncludeTables = $null => include all tables for migration
# DEFAULT: $ExcludeTables = $null => exclude no tables from migration
# Exclude list has higher priority than include list
# Array of qualified source table names which should be migrated
[string[]] $IncludeTables = @("migsourcedb.coupons", "migsourcedb.daily_cash_sheets");
[string[]] $ExcludeTables = $null;

LogMessage -Message "Creating the table map based on the user input and database table information ..." `
    -IsProcessing $true

$targetTables = $getTargetTablesTask.Output.DatabasesToTables."$TargetDatabaseName";
$sourceTables = $getSourceTablesTask.Output.DatabasesToTables."$SourceDatabaseName";
$tableMap = New-Object 'system.collections.generic.dictionary[string,string]';

$schemaPrefixLength = $($SourceDatabaseName + ".").Length;
$tableMappingError = $false
foreach ($srcTable in $sourceTables) {
    # Removing the database name prefix from the table name so that comparison
    # can be done in cases where database name given are different
    $tableName = $srcTable.Name.Substring($schemaPrefixLength, `
            $srcTable.Name.Length - $schemaPrefixLength)

    # In case the table is part of exclusion list then ignore the table
    if ($null -ne $ExcludeTables -and $ExcludeTables -contains $srcTable.Name) {
        continue;
    }

    # Either the include list is null or the table is part of the include list then add it in the mapping
    if ($null -eq $IncludeTables -or $IncludeTables -contains $srcTable.Name) {
        # Check if the table exists in the target. If not then log TABLE MAPPING ERROR
        if (-not ($targetTables | Where-Object { $_.name -ieq "$($TargetDatabaseName).$tableName" })) {
            $tableMappingError = $true
            Write-Host "TABLE MAPPING ERROR: $($targetTables.name) does not exists in target." -ForegroundColor Red
            continue;
        }

        $tableMap.Add("$($SourceDatabaseName).$tableName", "$($TargetDatabaseName).$tableName");
    }
}

# In case of any table mapping errors identified, throw an error and stop the process
if ($tableMappingError) { throw "ERROR: One or more table mapping errors were identified. Please see previous messages." }
# In case no tables are in the mapping then throw error
if ($tableMap.Count -le 0) { throw "ERROR: Could not create table mapping." }
LogMessage -Message "Migration table mapping created for $($tableMap.Count) tables."

创建和配置迁移任务输入

生成表映射后，将创建 Migrate.MySql.AzureDbForMySql 类型的迁移任务的输入，并配置属性。

以下脚本创建迁移任务，并设置连接、数据库名称和表映射。

# Create and configure the migration scenario based on the connections
# and the table mapping
$offlineMigTaskProperties = @{
    "input"    = @{
        "sourceConnectionInfo"  = $null;
        "targetConnectionInfo"  = $null;
        "selectedDatabases"     = $null;
        "optionalAgentSettings" = @{
            "EnableCacheBatchesInMemory"         = $true;
            "DisableIncrementalRowStatusUpdates" = $true;
        };
        "startedOn"             = $null;
    };
    "taskType" = "Migrate.MySql.AzureDbForMySql";
};
$offlineSelectedDatabase = @{
    "name"               = $null;
    "targetDatabaseName" = $null;
    "tableMap"           = $null;
};

LogMessage -Message "Preparing migration scenario configuration ..." -IsProcessing $true

# Select the database to be migrated
$offlineSelectedDatabase.name = $SourceDatabaseName;
$offlineSelectedDatabase.tableMap = New-Object PSObject -Property $tableMap;
$offlineSelectedDatabase.targetDatabaseName = $TargetDatabaseName;

# Set connection info and the database mapping
$offlineMigTaskProperties.input.sourceConnectionInfo = $sourceConnInfo;
$offlineMigTaskProperties.input.targetConnectionInfo = $targetConnInfo;
$offlineMigTaskProperties.input.selectedDatabases = @($offlineSelectedDatabase);
$offlineMigTaskProperties.input.startedOn = [System.DateTimeOffset]::UtcNow.ToString("O");

配置性能优化参数

PowerShell 模块中提供了几个可选参数，可以根据环境优化这些参数。这些参数可用于提高迁移任务的性能。所有这些参数都是可选的，其默认值为 NULL。

注意

在高级 SKU 上进行迁移时，以下性能配置显示增加了吞吐量。

WriteDataRangeBatchTaskCount = 12
DelayProgressUpdatesInStorageInterval = 30 seconds
ThrottleQueryTableDataRangeTaskAtBatchCount = 36

以下脚本获取参数的用户值，并设置迁移任务属性中的参数。

# Setting optional parameters from fine tuning the data transfer rate during migration
# DEFAULT values for all the configurations is $null
LogMessage -Message "Adding optional migration performance tuning configuration ..." -IsProcessing $true
# Partitioning settings
# Optional setting that configures the maximum number of parallel reads on tables located on the source database.
[object] $DesiredRangesCount = 4
# Optional setting that configures that size of the largest batch that will be committed to the target server.
[object] $MaxBatchSizeKb = 4096
# Optional setting that configures the minimum number of rows in each batch written to the target.
[object] $MinBatchRows = $null
# Task count settings
# Optional setting that configures the number of databases that will be prepared for migration in parallel.
[object] $PrepareDatabaseForBulkImportTaskCount = $null
# Optional setting that configures the number of tables that will be prepared for migration in parallel.
[object] $PrepareTableForBulkImportTaskCount = $null
# Optional setting that configures the number of threads available to read ranges on the source.
[object] $QueryTableDataRangeTaskCount = 8
# Optional setting that configures the number of threads available to write batches to the target.
[object] $WriteDataRangeBatchTaskCount = 12
# Batch cache settings
# Optional setting that configures how much memory will be used to cache batches in memory before reads on the source are throttled.
[object] $MaxBatchCacheSizeMb = $null
# Optional setting that configures the amount of available memory at which point reads on the source will be throttled.
[object] $ThrottleQueryTableDataRangeTaskAtAvailableMemoryMb = $null
# Optional setting that configures the number of batches cached in memory that will trigger read throttling on the source.
[object] $ThrottleQueryTableDataRangeTaskAtBatchCount = 36
# Performance settings
# Optional setting that configures the delay between updates of result objects in Azure Table Storage.
[object] $DelayProgressUpdatesInStorageInterval = "00:00:30"

function AddOptionalSetting($optionalAgentSettings, $settingName, $settingValue) {
    # If no value specified for the setting, don't bother adding it to the input
    if ($null -eq $settingValue) {
        return;
    }

    # Add a new property to the JSON object to capture the setting which will be customized
    $optionalAgentSettings | add-member -MemberType NoteProperty -Name $settingName -Value $settingValue
}

# Set any optional settings in the input based on parameters to this cmdlet
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "DesiredRangesCount" $DesiredRangesCount;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "MaxBatchSizeKb" $MaxBatchSizeKb;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "MinBatchRows" $MinBatchRows;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "PrepareDatabaseForBulkImportTaskCount" $PrepareDatabaseForBulkImportTaskCount;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "PrepareTableForBulkImportTaskCount" $PrepareTableForBulkImportTaskCount;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "QueryTableDataRangeTaskCount" $QueryTableDataRangeTaskCount;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "WriteDataRangeBatchTaskCount" $WriteDataRangeBatchTaskCount;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "MaxBatchCacheSizeMb" $MaxBatchCacheSizeMb;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "ThrottleQueryTableDataRangeTaskAtAvailableMemoryMb" $ThrottleQueryTableDataRangeTaskAtAvailableMemoryMb;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "ThrottleQueryTableDataRangeTaskAtBatchCount" $ThrottleQueryTableDataRangeTaskAtBatchCount;
AddOptionalSetting $offlineMigTaskProperties.input.optionalAgentSettings "DelayProgressUpdatesInStorageInterval" $DelayProgressUpdatesInStorageInterval;

创建并运行迁移任务

配置任务的输入后，现在将在代理上创建并执行任务。此脚本将触发任务执行并等待迁移完成。

以下脚本调用配置的迁移任务并等待任务完成。

# Running the migration scenario
[string] $TaskName = "mysqlofflinemigrate"

LogMessage -Message "Running data migration scenario ..." -IsProcessing $true
$summary = @{
    "SourceServer"   = $SourceServerName;
    "SourceDatabase" = $SourceDatabaseName;
    "TargetServer"   = $TargetServerName;
    "TargetDatabase" = $TargetDatabaseName;
    "TableCount"     = $tableMap.Count;
    "StartedOn"      = $offlineMigTaskProperties.input.startedOn;
}

Write-Host "Job Summary:" -ForegroundColor Yellow
Write-Host $(ConvertTo-Json $summary) -ForegroundColor Yellow

$migrationResult = RunScenario -MigrationService $dmsService `
    -MigrationProject $dmsProject `
    -ScenarioTaskName $TaskName `
    -TaskProperties $offlineMigTaskProperties

LogMessage -Message "Migration completed with status - $($migrationResult.state)"
#Checking for any errors or warnings captured by the task during migration
$dbLevelResult = $migrationResult.output | Where-Object { $_.resultType -eq "DatabaseLevelOutput" }
$migrationLevelResult = $migrationResult.output | Where-Object { $_.resultType -eq "MigrationLevelOutput" }
if ($dbLevelResult.exceptionsAndWarnings) {
    Write-Host "Following database errors were captured: $($dbLevelResult.exceptionsAndWarnings)" -ForegroundColor Red
}
if ($migrationLevelResult.exceptionsAndWarnings) {
    Write-Host "Following migration errors were captured: $($migrationLevelResult.exceptionsAndWarnings)" -ForegroundColor Red
}
if ($migrationResult.errors.details) {
    Write-Host "Following task level migration errors were captured: $($migrationResult.errors.details)" -ForegroundColor Red
}

删除数据库迁移服务

相同的数据库迁移服务可用于多次迁移，因此实例在创建后可以重复使用。如果不打算继续使用数据库迁移服务，则可以使用 Remove-AzDataMigrationService 命令删除该服务。

以下脚本删除 Azure 数据库迁移服务实例及其关联项目。

Remove-AzDataMigrationService -ResourceId $($dmsService.ResourceId)

后续步骤

有关使用 DMS 执行迁移时的已知问题和限制，请参阅常见问题 - Azure 数据库迁移服务一文。
要在使用 DMS 时排查源数据库连接问题，请参阅连接源数据库时的问题一文。
若要了解 Azure 数据库迁移服务，请参阅什么是 Azure 数据库迁移服务？一文。
若要了解 Azure Database for MySQL，请参阅什么是 Azure Database for MySQL？一文。
有关通过门户使用 DMS 的教程，请参阅教程：使用 DMS 将 MySQL 脱机迁移到 Azure Database for MySQL