Merge pull request #177885 from deborahc/dech-cosmos-partitioning-docs

Adding info on how splits get paused during add region and failover operations

Author: v-andreaco

articles/cosmos-db/how-to-manage-database-account.md

@@ -25,7 +25,7 @@ This article describes how to manage various tasks on an Azure Cosmos account us
 ## Add/remove regions from your database account
 
 > [!TIP]
-> When a new region is added, all data must be fully replicated and committed into the new region before the region is marked as available. The amount of time this operation takes will depend upon how much data is stored within the account.
+> When a new region is added, all data must be fully replicated and committed into the new region before the region is marked as available. The amount of time this operation takes will depend upon how much data is stored within the account. If an [asynchronous throughput scaling operation](scaling-provisioned-throughput-best-practices.md#background-on-scaling-rus) is in progress, the throughput scale-up operation will be paused and will resume automatically when the add/remove region operation is complete. 
 
 1. Sign in to [Azure portal](https://portal.azure.com).
 
@@ -91,6 +91,9 @@ After a Cosmos account is configured for automatic failover, the failover priori
 > [!IMPORTANT]
 > The Azure Cosmos account must be configured for manual failover for this operation to succeed.
 
+> [!NOTE]
+> If you perform a manual failover operation while an [asynchronous throughput scaling operation](scaling-provisioned-throughput-best-practices.md#background-on-scaling-rus) is in progress, the throughput scale-up operation will be paused. It will resume automatically when the failover operation is complete.
+
 1. Go to your Azure Cosmos account, and open the **Replicate data globally** menu.
 
 2. At the top of the menu, select **Manual Failover**.

articles/cosmos-db/how-to-move-regions.md

@@ -36,6 +36,9 @@ Azure Cosmos DB supports data replication natively, so moving data from one regi
 
     To remove a region from an Azure Cosmos DB account, see [Add/remove regions from your Azure Cosmos DB account](how-to-manage-database-account.md#addremove-regions-from-your-database-account).
 
+> [!NOTE]
+> If you perform a failover operation or add/remove a new region while an [asynchronous throughput scaling operation](scaling-provisioned-throughput-best-practices.md#background-on-scaling-rus) is in progress, the throughput scale-up operation will be paused. It will resume automatically when the failover or add/remove region operation is complete. 
+
 ## Migrate Azure Cosmos DB account metadata
 
 Azure Cosmos DB does not natively support migrating account metadata from one region to another. To migrate both the account metadata and customer data from one region to another, you must create a new account in the desired region and then copy the data manually. 

articles/cosmos-db/scaling-provisioned-throughput-best-practices.md

@@ -30,10 +30,12 @@ When you send a request to increase the RU/s of your database or container, depe
     - As a result, the operation can take some time to complete, typically 4-6 hours.
 Each physical partition can support a maximum of 10,000 RU/s (applies to all APIs) of throughput and 50 GB of storage (applies to all APIs, except Cassandra, which has 30 GB of storage). 
 
+> [!NOTE]
+> If you perform a [manual region failover operation](how-to-manage-database-account.md#manual-failover) or [add/remove a new region](how-to-manage-database-account.md#addremove-regions-from-your-database-account) while an asynchronous scale-up operation is in progress, the throughput scale-up operation will be paused. It will resume automatically when the failover or add/remove region operation is complete. 
 - **Instant scale-down**
     - For scale down operation Azure Cosmos DB doesn’t need to split or add new partitions. 
     - As a result, the operation completes immediately and the RU/s are available for use, 
-    - Key result of this operation is that RUs per partition range will be reduced.
+    - Key result of this operation is that RUs per physical partition will be reduced.
 
 ## How to scale-up RU/s without changing partition layout
 

articles/cosmos-db/sql/manage-with-cli.md

@@ -66,7 +66,7 @@ Create an Azure Cosmos account with two regions, add a region, and remove a regi
 > [!NOTE]
 > This command allows you to add and remove regions but does not allow you to modify failover priorities or trigger a manual failover. See [Set failover priority](#set-failover-priority) and [Trigger manual failover](#trigger-manual-failover).
 > [!TIP]
-> When a new region is added, all data must be fully replicated and committed into the new region before the region is marked as available. The amount of time this operation takes will depend upon how much data is stored within the account.
+> When a new region is added, all data must be fully replicated and committed into the new region before the region is marked as available. The amount of time this operation takes will depend upon how much data is stored within the account. If an [asynchronous throughput scaling operation](../scaling-provisioned-throughput-best-practices.md#background-on-scaling-rus) is in progress, the throughput scale-up operation will be paused and will resume automatically when the add/remove region operation is complete. 
 
 ```azurecli-interactive
 resourceGroupName='myResourceGroup'
@@ -139,6 +139,9 @@ az cosmosdb update --ids $accountId --enable-automatic-failover true
 > [!CAUTION]
 > Changing region with priority = 0 will trigger a manual failover for an Azure Cosmos account. Any other priority change will not trigger a failover.
 
+> [!NOTE]
+> If you perform a manual failover operation while an [asynchronous throughput scaling operation](../scaling-provisioned-throughput-best-practices.md#background-on-scaling-rus) is in progress, the throughput scale-up operation will be paused. It will resume automatically when the failover operation is complete.
+
 ```azurecli-interactive
 # Assume region order is initially 'West US 2=0' 'East US 2=1' 'South Central US=2' for account
 resourceGroupName='myResourceGroup'

articles/cosmos-db/sql/manage-with-powershell.md

@@ -116,7 +116,7 @@ This command allows you to update your Azure Cosmos DB database account properti
 > [!NOTE]
 > This command allows you to add and remove regions but does not allow you to modify failover priorities or trigger a manual failover. See [Modify failover priority](#modify-failover-priority) and [Trigger manual failover](#trigger-manual-failover).
 > [!TIP]
-> When a new region is added, all data must be fully replicated and committed into the new region before the region is marked as available. The amount of time this operation takes will depend upon how much data is stored within the account.
+> When a new region is added, all data must be fully replicated and committed into the new region before the region is marked as available. The amount of time this operation takes will depend upon how much data is stored within the account. If an [asynchronous throughput scaling operation](../scaling-provisioned-throughput-best-practices.md#background-on-scaling-rus) is in progress, the throughput scale-up operation will be paused and will resume automatically when the add/remove region operation is complete. 
 
 ```azurepowershell-interactive
 # Create account with two regions
@@ -319,6 +319,9 @@ For the example below, assume the account has a current failover priority of `We
 > [!CAUTION]
 > Changing `locationName` for `failoverPriority=0` will trigger a manual failover for an Azure Cosmos account. Any other priority change will not trigger a failover.
 
+> [!NOTE]
+> If you perform a manual failover operation while an [asynchronous throughput scaling operation](../scaling-provisioned-throughput-best-practices.md#background-on-scaling-rus) is in progress, the throughput scale-up operation will be paused. It will resume automatically when the failover operation is complete.
+
 ```azurepowershell-interactive
 $resourceGroupName = "myResourceGroup"
 $accountName = "mycosmosaccount"