added backup to url file

Author: MashaMSFT

docs/relational-databases/backup-restore/sql-server-backup-to-url.md

@@ -16,49 +16,22 @@ ms.author: mathoma
 
   This topic introduces the concepts, requirements and components necessary to use the Microsoft Azure Blob storage service as a backup destination. The backup and restore functionality are same or similar to when using DISK or TAPE, with a few differences. These differences and a few code examples are included in this topic.  
 
-## Requirements, Components, and Concepts  
- **In this section:**  
-  
--   [Security](#security)  
-  
--   [Introduction to Key Components and Concepts](#intorkeyconcepts)  
-  
--   [Microsoft Azure Blob storage service](#Blob)  
-  
--   [SQL Server Components](#sqlserver)  
-  
--   [Limitations](#limitations)  
-  
--   [Support for Backup/Restore Statements](#Support)  
-  
--   [Using Backup Task in SQL Server Management Studio](../../relational-databases/backup-restore/sql-server-backup-to-url.md#BackupTaskSSMS)  
-  
--   [SQL Server Backup to URL Using Maintenance Plan Wizard](../../relational-databases/backup-restore/sql-server-backup-to-url.md#MaintenanceWiz)  
-  
--   [Restoring from Azure storage Using SQL Server Management Studio](../../relational-databases/backup-restore/sql-server-backup-to-url.md#RestoreSSMS)  
-  
-###  <a name="security"></a> Security  
- The following are security considerations and requirements when backing up to or restoring from the Microsoft Azure Blob storage service.  
-  
--   When creating a container for the Microsoft Azure Blob storage service, we recommend that you set the access to **private**. Setting the access to private restricts the access to users or accounts able to provide the necessary information to authenticate to the Azure account.  
-  
-    > [!IMPORTANT]  
-    >  [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] requires that either an Azure account name and access key authentication or a Shared Access Signature and access token be stored in a [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Credential. This information is used to authenticate to the Azure account when performing backup or restore operations.  
-  
--   The user account that is used to issue BACKUP or RESTORE commands should be in the **db_backup operator** database role with **Alter any credential** permissions.  
-  
-###  <a name="intorkeyconcepts"></a> Introduction to Key Components and Concepts  
- The following two sections introduce the Microsoft Azure Blob storage service, and the [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] components used when backing up to or restoring from the Microsoft Azure Blob storage service. It is important to understand the components and the interaction between them to do a backup to or restore from the Microsoft Azure Blob storage service.  
+
+## Overview
+  It is important to understand the components and the interaction between them to do a backup to or restore from the Microsoft Azure Blob storage service.  
 
  Creating an Azure Storage account within your Azure subscription is the first step in this process. This storage account is an administrative account that has full administrative permissions on all containers and objects created with the storage account. [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] can either use the Azure storage account name and its access key value to authenticate and write and read blobs to the Microsoft Azure Blob storage service or use a Shared Access Signature token generated on specific containers granting it read and write rights. For more information on Azure Storage Accounts, see [About Azure Storage Accounts](https://azure.microsoft.com/documentation/articles/storage-create-storage-account/) and for more information about Shared Access Signatures, see [Shared Access Signatures, Part 1: Understanding the SAS Model](https://azure.microsoft.com/documentation/articles/storage-dotnet-shared-access-signature-part-1/). The [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Credential stores this authentication information and is used during the backup or restore operations.  
 
 ###  <a name="blockbloborpageblob"></a> Backup to block blob vs. page blob 
  There are two types of blobs that can be stored in the Microsoft Azure Blob storage service: block and page blobs. SQL Server backup can use either blob type depending upon the Transact-SQL syntax used: If the storage key is used in the credential, page blob will be used; if the Shared Access Signature is used, block blob will be used.
 
- Backup to block blob is only available in SQL Server 2016 or later version. We recommend you to backup to block blob instead of page block if you are running SQL Server 2016 or later version. The main reasons are:
+ Backup to block blob is only available in SQL Server 2016 or later version. Backup to block blob instead of page blob if you are running SQL Server 2016 or later. 
+ The main reasons are:
 - Shared Access Signature is a safer way to authorize blob access compared to storage key.
 - You can backup to multiple block blobs to get better backup and restore performance, and support larger database backup.
 - [Block blob](https://azure.microsoft.com/pricing/details/storage/blobs/) is cheaper than [page blob](https://azure.microsoft.com/pricing/details/storage/page-blobs/). 
+- Customers that need to backup to page blobs via a proxy server will need to use backuptourl.exe. 
+
 
 Backup of a large database to blob storage is subject to the limitations listed in [Managed instance T-SQL differences, limitations, and known issues](/azure/sql-database/sql-database-managed-instance-transact-sql-information#backup).
 
@@ -91,7 +64,17 @@ Backup of a large database to blob storage is subject to the limitations listed
 
  For information on other examples where credentials are used, see [Create a SQL Server Agent Proxy](../../ssms/agent/create-a-sql-server-agent-proxy.md).  
 
-###  <a name="limitations"></a> Limitations  
+##  <a name="security"></a> Security  
+ The following are security considerations and requirements when backing up to or restoring from the Microsoft Azure Blob storage service.  
+  
+-   When creating a container for the Microsoft Azure Blob storage service, we recommend that you set the access to **private**. Setting the access to private restricts the access to users or accounts able to provide the necessary information to authenticate to the Azure account.  
+  
+    > [!IMPORTANT]  
+    >  [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] requires that either an Azure account name and access key authentication or a Shared Access Signature and access token be stored in a [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] Credential. This information is used to authenticate to the Azure account when performing backup or restore operations.  
+  
+-   The user account that is used to issue BACKUP or RESTORE commands should be in the **db_backup operator** database role with **Alter any credential** permissions.   
+
+##  <a name="limitations"></a> Limitations  
 
 -   Backup to premium storage is not supported.  
 
@@ -112,7 +95,13 @@ Backup of a large database to blob storage is subject to the limitations listed
 -   Specifying backupset options - **RETAINDAYS** and **EXPIREDATE** are not supported.  
 
 -   [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] has a maximum limit of 259 characters for a backup device name. The BACKUP TO URL consumes 36 characters for the required elements used to specify the URL - 'https://.blob.core.windows.net//.bak', leaving 223 characters for account, container, and blob names put together.  
+
+- If your server accesses Azure via a proxy server, you must use trace flag 1819 and then set the WinHTTP proxy configuration via one of the following methods:
+   - The [proxycfg.exe](/windows/win32/winhttp/proxycfg-exe--a-proxy-configuration-tool) utility on Windows XP or Windows Server 2003 and earlier. 
+   - The [netsh.exe](/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/cc731131) utility on Windows Vista and Windows Server 2008 or later. 
 
+## Supported arguments & statements
+
 ###  <a name="Support"></a> Support for Backup/Restore Statements  
 
 |Backup/Restore Statement|Supported|Exceptions|Comments|
@@ -202,7 +191,7 @@ Backup of a large database to blob storage is subject to the limitations listed
 
  For more information about Restore arguments, see [RESTORE Arguments &#40;Transact-SQL&#41;](../../t-sql/statements/restore-statements-arguments-transact-sql.md).  
 
-##  <a name="BackupTaskSSMS"></a> Using Back Up Task in SQL Server Management Studio  
+##  <a name="BackupTaskSSMS"></a> Back up up with SSMS  
 You can back up a database to URL through the Back Up task in SQL Server Management Studio using a SQL Server Credential.  
 
 > [!NOTE]  
@@ -236,13 +225,13 @@ When you select **URL** as the destination, certain options in the **Media Optio
 
  [Create Credential - Authenticate to Azure Storage](../../relational-databases/backup-restore/create-credential-authenticate-to-azure-storage.md)  
 
-##  <a name="MaintenanceWiz"></a> SQL Server Backup to URL Using Maintenance Plan Wizard  
+##  <a name="MaintenanceWiz"></a> Back up with maintenance plan  
  Similar to the backup task described previously, the Maintenance Plan Wizard in SQL Server Management Studio includes **URL** as one of the destination options, and other supporting objects required to backup to Azure storage like the SQL Credential. It has the same For more information, see the **Define Backup Tasks** section in [Using Maintenance Plan Wizard](../../relational-databases/maintenance-plans/use-the-maintenance-plan-wizard.md#SSMSProcedure).  
 
 > [!NOTE]  
 >  To create a striped backup set, a [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] file-snapshot backup, or a SQL credential using Shared Access token, you must use Transact-SQL, Powershell or C# rather than the Backup task in Maintenance Plan Wizard.  
   
-##  <a name="RestoreSSMS"></a> Restoring from Microsoft Azure storage Using SQL Server Management Studio  
+##  <a name="RestoreSSMS"></a> Restore with SSMS 
 The Restore Database task includes **URL** as a device to restore from.  The following steps describe using the Restore task to restore from the Microsoft Azure Blob storage service: 
 
 1.  Right-click **Databases** and select **Restore Database...**. 
@@ -259,7 +248,7 @@ The Restore Database task includes **URL** as a device to restore from.  The fol
 
     3.  **Add:**  Used to register an existing container that you do not have a shared access signature for.  See [Connect to a Microsoft Azure Subscription](../../relational-databases/backup-restore/connect-to-a-microsoft-azure-subscription.md).
 
-    4.  **OK:**	SQL Server connects to Microsoft Azure storage using the SQL Credential information you provided and opens the **Locate Backup File in Microsoft Azure** dialog. The backup files residing in the storage container are displayed on this page. Select the file you want to use to restore and click **OK**. This takes you back to the **Select Backup Devices** dialog, and clicking **OK** on this dialog takes you back to the main **Restore** dialog where you will be able complete the restore. 
+    4.  **OK:**    SQL Server connects to Microsoft Azure storage using the SQL Credential information you provided and opens the **Locate Backup File in Microsoft Azure** dialog. The backup files residing in the storage container are displayed on this page. Select the file you want to use to restore and click **OK**. This takes you back to the **Select Backup Devices** dialog, and clicking **OK** on this dialog takes you back to the main **Restore** dialog where you will be able complete the restore. 
 
      [Restore Database &#40;General Page&#41;](../../relational-databases/backup-restore/restore-database-general-page.md)