Merge pull request #7283 from MicrosoftDocs/FromPublicRepo

huypub · web-flow · commit ee637456dfae · 2018-09-17T15:06:09.000-07:00
Confirm merge from FromPublicRepo to master to sync with
diff --git a/docs/advanced-analytics/tutorials/deepdive-define-and-use-compute-contexts.md b/docs/advanced-analytics/tutorials/deepdive-define-and-use-compute-contexts.md
@@ -86,7 +86,7 @@ The function that creates the SQL Server compute context uses the following info
 
 ## Enable tracing on the compute context
 
-Sometimes operations work on your local context, but have issues when running in a remote compute context. if you want to analyze issues or monitor performance, you can enable tracing in the compute context, to support run-time troubleshooting.
+Sometimes operations work on your local context, but have issues when running in a remote compute context. If you want to analyze issues or monitor performance, you can enable tracing in the compute context, to support run-time troubleshooting.
 
 1. Create a new compute context that uses the same connection string, but add the arguments *traceEnabled* and *traceLevel* to the **RxInSqlServer** constructor.
 
diff --git a/docs/advanced-analytics/tutorials/deepdive-query-and-modify-the-sql-server-data.md b/docs/advanced-analytics/tutorials/deepdive-query-and-modify-the-sql-server-data.md
@@ -53,7 +53,7 @@ First, get a list of the columns and their data types.
 
 ## Modify metadata
 
-All the variables are stored as integers, but some variables represent categorical data,called *factor variables* in R. For example, the column *state* contains numbers used as identifiers for the 50 states plus the District of Columbia.  To make it easier to understand the data, you replace the numbers with a list of state abbreviations.
+All the variables are stored as integers, but some variables represent categorical data, called *factor variables* in R. For example, the column *state* contains numbers used as identifiers for the 50 states plus the District of Columbia.  To make it easier to understand the data, you replace the numbers with a list of state abbreviations.
 
 In this step, you create a string vector containing the abbreviations, and then map these categorical values to the original integer identifiers. Then you use the new variable in the *colInfo* argument, to specify that this column be handled as a factor. Whenever you analyze the data or move it, the abbreviations are used and the column is handled as a factor.
 
diff --git a/docs/relational-databases/backup-restore/sql-server-backup-to-url-best-practices-and-troubleshooting.md b/docs/relational-databases/backup-restore/sql-server-backup-to-url-best-practices-and-troubleshooting.md
@@ -24,7 +24,7 @@ manager: craigg
   
 -   [SQL Server Backup and Restore with Microsoft Azure Blob Storage Service](../../relational-databases/backup-restore/sql-server-backup-and-restore-with-microsoft-azure-blob-storage-service.md)  
   
--   [Tutorial: SQL Server Backup and Restore to Windows Azure Blob Storage Service](~/relational-databases/tutorial-sql-server-backup-and-restore-to-azure-blob-storage-service.md)  
+-   [Tutorial: SQL Server Backup and Restore to Windows Azure Blob Storage Service](../../relational-databases/tutorial-sql-server-backup-and-restore-to-azure-blob-storage-service.md)  
   
 ## Managing Backups  
  The following list includes general recommendations to manage backups:  
@@ -87,7 +87,24 @@ manager: craigg
         -   **VERIFYONLY**  
   
     -   You can also find information by reviewing the Windows Event Log - Under Application logs with the name `SQLBackupToUrl`.  
-  
+
+    -   Consider COMPRESSION, MAXTRANSFERSIZE, BLOCKSIZE and multiple URL arguments when backing up large databases.  See [Backing up a VLDB to Azure Blob Storage](https://blogs.msdn.microsoft.com/sqlcat/2017/03/10/backing-up-a-vldb-to-azure-blob-storage/)
+  
+		```
+		Msg 3202, Level 16, State 1, Line 1
+		Write on "https://mystorage.blob.core.windows.net/mycontainer/TestDbBackupSetNumber2_0.bak" failed: 1117(The request could not be performed because of an I/O device error.)
+		Msg 3013, Level 16, State 1, Line 1
+		BACKUP DATABASE is terminating abnormally.
+		```
+
+        ```sql  
+        BACKUP DATABASE TestDb
+        TO URL = 'https://mystorage.blob.core.windows.net/mycontainer/TestDbBackupSetNumber2_0.bak',
+        URL = 'https://mystorage.blob.core.windows.net/mycontainer/TestDbBackupSetNumber2_1.bak',
+        URL = 'https://mystorage.blob.core.windows.net/mycontainer/TestDbBackupSetNumber2_2.bak'
+        WITH COMPRESSION, MAXTRANSFERSIZE = 4194304, BLOCKSIZE = 65536;  
+        ```  
+
 -   When restoring from a compressed backup, you might see the following error:  
   
     -   `SqlException 3284 occurred. Severity: 16 State: 5  
diff --git a/docs/relational-databases/backup-restore/sql-server-backup-to-url.md b/docs/relational-databases/backup-restore/sql-server-backup-to-url.md
@@ -56,6 +56,18 @@ manager: craigg
   
  Creating a Windows 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 Windows 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](http://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](http://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:
+- 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/). 
+
+When you backup to block blob, the maximum block size you can specify is 4MB. The maximum size of a single block blob file is 4MB * 50000 = 195GB. If your database is larger than 195GB, we recommend you:
+- Use backup compression
+- Backup to multiple block blobs
+
 ###  <a name="Blob"></a> Microsoft Azure Blob storage service  
  **Storage Account:** The storage account is the starting point for all storage services. To access the Microsoft Azure Blob storage service, first create a Windows Azure storage account. For more information, see [Create a Storage Account](http://azure.microsoft.com/documentation/articles/storage-create-storage-account/)  
   
diff --git a/docs/t-sql/statements/create-external-file-format-transact-sql.md b/docs/t-sql/statements/create-external-file-format-transact-sql.md
@@ -301,7 +301,7 @@ Notes about the table:
 ## Performance
  Using compressed files always comes with the tradeoff between transferring less data between the external data source and SQL Server while increasing the CPU usage to compress and decompress the data.
   
- Gzip compressed text files are not splittable. To improve performance for Gzip compressed text files, we recommend generating multiple files that are all stored in the same directory within the external data source. This file structure allows PolyBase to read and decompress the data faster by using multiple reader and decompression processes. The ideal number of compressed files is the maximum number of data reader processes per compute node. In [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] and [!INCLUDE[ssPDW](../../includes/sspdw-md.md)], the maximum number of data reader processes is 8 per node in the current release. In [!INCLUDE[ssSDW](../../includes/sssdw-md.md)], the maximum number of data reader processes per node varies by SLO. See [Azure SQL Data Warehouse loading patterns and strategies](https://blogs.msdn.microsoft.com/sqlcat/2016/02/06/azure-sql-data-warehouse-loading-patterns-and-strategies/) for details.  
+ Gzip compressed text files are not splittable. To improve performance for Gzip compressed text files, we recommend generating multiple files that are all stored in the same directory within the external data source. This file structure allows PolyBase to read and decompress the data faster by using multiple reader and decompression processes. The ideal number of compressed files is the maximum number of data reader processes per compute node. In [!INCLUDE[ssNoVersion](../../includes/ssnoversion-md.md)] and [!INCLUDE[ssPDW](../../includes/sspdw-md.md)], the maximum number of data reader processes is 8 per node except Azure SQL Data Warehouse Gen2 which is 20 readers per node. In [!INCLUDE[ssSDW](../../includes/sssdw-md.md)], the maximum number of data reader processes per node varies by SLO. See [Azure SQL Data Warehouse loading patterns and strategies](https://blogs.msdn.microsoft.com/sqlcat/2016/02/06/azure-sql-data-warehouse-loading-patterns-and-strategies/) for details.  
   
 ## Examples  
   
